Introduction (Magill’s Medical Guide, Sixth Edition)
The term “marijuana” refers to both the illegal drug and the plant itself. The hemp plant, Cannabis sativa, is a fast-growing (to fifteen feet), bushy annual with finely branched leaves further divided into lance-shaped, sawtooth-edged leaflets. The species was first classified in 1735 by the Swedish botanist Carolus Linnaeus. Both male and female plants produce tetrahydrocannabinol (THC), the psychoactive ingredient in the drug. THC collects in tiny droplets of sticky resin produced by glands located at the base of fine hairs covering most of the plant’s surface, with the most highly concentrated THC found in the female flower heads. When pollinated, however, the female flower heads produce highly nutritious seeds containing no THC.
(The entire section is 113 words.)
Recreational and Medicinal Uses (Magill’s Medical Guide, Sixth Edition)
Marijuana ranks as the third most commonly used recreational drug in the Western world, behind alcohol and tobacco. It is usually smoked, but it can be eaten or brewed as tea. Responses vary according to dosage and experience using the drug, but most people experience a mild euphoria, or “high.” Mood, short-term memory, motor coordination, thought, sensation, and time sense can all be affected. Hunger, known as “the munchies,” frequently occurs soon after exposure. The heart rate increases, the blood pressure increases while supine but drops when standing, and the eyes can become bloodshot. The most rapid onset with most temporary effect occurs with smoked marijuana. Unlike alcohol or tobacco, no deaths have been directly attributed to marijuana use alone.
Marijuana has been cultivated and used as a medicine for thousands of years. The Food and Drug Administration (FDA) has approved a synthetic formulation of THC, Marinol (brand name of the generic drug dronabinol), that doctors can prescribe legally for the treatment of nausea and vomiting associated with cancer chemotherapy and the loss of appetite and weight loss characteristic of patients with acquired immunodeficiency syndrome (AIDS). In addition, both Marinol and marijuana are used to alleviate pain, muscle spasms, neurological disorders, and glaucoma. Many users of medicinal THC prefer to smoke marijuana despite its illegality rather than take...
(The entire section is 279 words.)
Perspective and Prospects (Magill’s Medical Guide, Sixth Edition)
Despite the FDA’s tacit acknowledgment of the medicinal value of marijuana by the approval of Marinol, marijuana itself is classified as a substance with high potential for abuse and no accepted medical use under federal drug laws, stifling research into other potential medical benefits. Scientific evidence, including the 1990 report of the National Academy of Sciences Marijuana and Medicine: Assessing the Science Base, strongly supports further research.
(The entire section is 67 words.)
For Further Information: (Magill’s Medical Guide, Sixth Edition)
Earleywine, Mitch. Understanding Marijuana: A New Look at the Scientific Evidence. New York: Oxford University Press, 2002.
ElSohly, Mahmoud A., ed. Marijuana and the Cannabinoids. Totowa, N.J.: Humana Press, 2007.
Iversen, Leslie L. The Science of Marijuana. New York: Oxford University Press, 2000.
Mack, Alison, and Janet Joy. Marijuana as Medicine? The Science Beyond the Controversy. Washington, D.C.: National Academy Press, 2001.
Onaivi, Emmanuel S., ed. Marijuana and Cannabinoid Research: Methods and Protocols. Totowa, N.J.: Humana Press, 2006.
Shohov, Tatiana, ed. Medical Use of Marijuana: Policy, Regulatory, and Legal Issues. New York: Nova Science, 2003.
(The entire section is 92 words.)
Marijuana (Encyclopedia of Cancer)
Marijuana and its medically active components, called cannabinoids, are used in cancer therapy to reduce nausea and vomiting caused by chemotherapeutic medications. This drug, however, is considered an illegal substance in the United States.
Marijuana can be used with a variety of cancer chemotherapeutic agents that cause nausea and vomiting. Marijuana seems to work best at preventing nausea and vomiting with mild to moderately active chemotherapeutic agents. There are limited studies showing it does help reduce nausea and vomiting caused by the most powerful cancer chemotheraupeutic drugs. Marijuana may also be used by cancer patients to stimulate appetite.
Marijuana, a plant with known psychoactive properties, has been used by human beings for thousands of years as a medicine. Ancient Chinese writings tell of its use for headaches, menstrual pains, and abdominal distress. It was used in the United States as a medicine for a variety of aliments until 1937, when its use was discouraged by the Marijuana Tax Act, which imposed high taxes on its use. In 1970, it was classified by the U.S....
(The entire section is 994 words.)
Marijuana (Encyclopedia of Medicine)
Marijuana (marihuana) Cannabis sativa L., also known as Indian hemp, is a member of the Cannabaceae or hemp family, thought to have originated in the mountainous districts of India, north of the Himalayan mountains.
The herb was referred to as "hempe" in A.D. 1000 and listed in a dictionary under that English name. Supporters of the notorious Pancho Villa first used the name marijuana in 1895 in Sonora, Mexico. They called the mood-altering herb they smoked marijuana. The term hashish, is derived from the name for the Saracen soldiers, called hashashins, who ingested the highly potent cannabis resin before being sent out to assassinate enemies.
Two related species of cannabis are C. ruderalis, and C. indica, a variety known as Indian hemp. Indian hemp grows to a height of about 4 ft (1.2 m) and the seed coats have a marbled appearance.
The species C. sativa L. has many variations, depending on the soil, temperature, and light conditions, and the origin of the parent seed. These factors also affect the relative amounts of THC (tetra-hydrocannabinol) and cannabidiol, the chemicals present in varying amounts in cannabis that determine if the plant is primarily a fiber type or an intoxicant. Generally the species grown at higher...
(The entire section is 2783 words.)
Marijuana (Encyclopedia of Science)
Marijuana is the common name for the drug obtained from the hemp plant, Cannabis sativa. Hemp is a tall annual plant that can grow in almost any climate. Native to central and western Asia, hemp is one of the oldest crops cultivated by humans. Hemp's most common agricultural use has been as a source of linen, rope, canvas, and paper.
Hemp contains more than 400 chemicals. The main psychoactive (affecting the mind or behavior) chemical is tetrahydrocannabinol, commonly referred to as THC. For over 3,000 years, the dried ground leaves, flowers, and stems of the plant have been smoked, eaten, chewed, or brewed as a medicine to relieve symptoms of illness. From the seventeenth to the early twentieth century, marijuana was considered a household drug useful for treating such maladies as headaches, menstrual cramps, and toothaches.
In the 1920s, as a result of the Eighteenth Amendment to the U.S. Constitution forbidding the manufacture and sale of alcoholic beverages (Prohibition), the use of marijuana as a psychoactive drug began to grow. Even after the repeal of Prohibition in 1933, marijuana (along with morphine, heroin, and cocaine) continued to be widely used. In 1937, 46 states banned the use of marijuana.
In 1985, the Food and Drug Administration (FDA) gave approval for the use of two psychoactive chemicals from marijuana to prevent nausea and...
(The entire section is 988 words.)
Marijuana (Encyclopedia of Psychology)
The common name of a small number of varieties of Cannabis sativa, or Indian hemp plant, which contain tetrahydrocannabinol (THC), a psychoactive drug.
Cannabis, in the form of marijuana, hashish (a dried resinous material that seeps from cannabis leaves and is more potent than marijuana), or other cannabinoids, is probably the most often used illegal substance in the world. In the United States, marijuana use became widespread among young people in the 1960s. By 1979, 68 percent of young adults between the ages of 18 and 25 had experimented with it at least once, and it was reported that as of the same year the total number of people in the U.S. who had tried the drug was 50 million. In the late 1980s, it was estimated that about 50 to 60 percent of people between the ages of 21 and 29 had tried marijuana at least once.
Marijuana and hashish are usually smoked, but may also be ingested orally, and are sometimes added to food or beverages. The psychoactive substance of cannabis is tetrahydrocannabinol, or THC, especially delta-9-tetrahydrocannabinol. Delta-9-THC can be synthesized, is known to affect the central nervous system, and has been legally used to treat side-effects of chemotherapy and weight loss in persons affected with AIDS. Other legal therapeutic uses of marijuana include the treatment of glaucoma and...
(The entire section is 612 words.)
Marijuana (Encyclopedia of Alternative Medicine)
Marijuana (marihuana), Cannabis sativa L., also known as Indian hemp, is a member of the Cannabaceae or hemp family, thought to have originated in the mountainous districts of India, north of the Himalayan mountains. The herb was referred to as "hempe" in A.D. 1000 and listed in a dictionary under that English name. Supporters of the notorious Pancho Villa first called the mood-altering herb they smoked marijuana in 1895 in Sonora, Mexico. The term hashish, is derived from the name for the Saracen soldiers, called hashashins, who ingested the highly potent cannabis resin before being sent out to assassinate enemies.
Two related species of cannabis are C. ruderalis and C. indica, a variety known as Indian hemp. Indian hemp grows to a height of about 4 ft (1.2 m) and the seed coats have a marbled appearance.
The species C. sativa L. has many variations, depending on the origin of the parent seed and the soil, temperature, and light conditions. These factors also affect the relative amounts of THC (tetra-hydrocannabinol) and cannabidiol, the chemicals present in varying amounts in cannabis that determine if the plant is primarily a fiber type or an intoxicant. Generally the species grown at higher elevations and in hotter climates exudes more of the resin and is more medicinally potent....
(The entire section is 2909 words.)
Marijuana (Encyclopedia of Nursing & Allied Health)
Marijuana is prepared from the leaves and flowering tops of Cannabis sativa, the hemp plant, which contains a number of pharmacologically active principles, called cannabinoids.
Marijuana is most popularly used for its euphoric properties. Its many nicknames include grass, pot, Mary Jane, reefer, and cannabis, which is derived from Cannabis sativa, the scientific name for hemp.
The beneficial effects of marijuana's most active ingredient, tetrahydrocannabinol (THC), include the lowering of intraocular pressure, which may help control glaucoma, and the relief of pain, nausea, and appetite loss among chemotherapy and AIDS patients.
Marijuana's short-term effects are psychological and physical, usually lasting for three to five hours after a person has smoked marijuana. The psychological reaction, more commonly known as a high, involves changes in the user's feelings and thoughts. These changes are primarily caused by THC, which affects brain function.
The effects of marijuana's high vary for each individual. In most cases the high consists of a dreamy, relaxed state in which users seem more aware of their senses and feel that time is moving slowly. Sometimes, however, marijuana produces feelings of panic and dread. Reactions vary according to the concentration of THC, the setting in which marijuana is used, and the user's expectations, personality, and mood.
Marijuana's short-term physical effects include reddening of the eyes and rapid heartbeat. The drug interferes with the individual's judgment, coordination, and short-term memory.
Long-term effects are not completely known. Marijuana use affects memory and motivation. Some chronic users experience bronchitis, coughing, and chest pains. Among males marijuana use can reduce sperm production and testosterone level. Among females it can cause menstrual irregularity and reduced fertility. Extended marijuana use often has a psychological impact and may result in the loss of interest in, for example, school, work, and social activities. Some regular marijuana users become dependent on it.
Marijuana affects psychomotor performance. The effects depend on the nature of the task and the individual's experience with marijuana. Cannabinoids, especially THC, can impact immune response, either enhancing or diminishing it.
Human volunteers performing auditory attention tasks while smoking marijuana show impaired performance, which is associated with substantial reduction in blood flow to the brain's temporal lobe. However, marijuana smoking increases blood flow in other brain regions, such as the frontal lobes and lateral cerebellum. Although some studies purported to show structural changes in the brains of heavy marijuana users, these results have not been replicated with more sophisticated techniques. Nevertheless, some studies have found subtle defects in the performance of cognitive tasks among heavy marijuana users.
THC narrows bronchi and bronchioles and produces inflammation of the mucous membranes. Marijuana smoke contains many of the same chemicals and tars of tobacco smoke and therefore increases the risk of lung cancer.
Although a distinctive marijuana withdrawal syndrome has been identified, it is mild and short-lived. Symptoms include restlessness, irritability, mild agitation, insomnia, sleep disturbance, nausea, and cramping.
Marijuana has been used as a medicine and intoxicant for thousands of years. In the United States, marijuana use has been prohibited by state and local laws since the early 1900s, and by federal law since 1937. In spite of these laws, use of the drug became widespread during the 1960s and 1970s. Between 1969 and 1978, the federal and many state governments reduced the criminal charge for possession of small amounts of marijuana from a felony to a misdemeanor. Some states even substituted fines for jail sentences. Use of marijuana in the United States declined from the mid-1970s through the early 1990s. In the mid-1990s, however, marijuana use again began to rise.
The Institute of Medicine recently released its findings on the medical merits of marijuana. Initially commissioned by the Office of National Drug Control Policy in 1997, the study concluded that cannabinoids, marijuana's active components, can be useful in treating pain, nausea and appetite loss caused by advanced cancer and AIDS. For very ill patients with no other treatment options, investigators recommended short-term use of smoked marijuana under strict medical oversight. However, the Institute of Medicine found that the drug's benefits were hampered by the toxicity of smoking, and that marijuana's future lay in the development of synthetic cannabinoids and in smokeless delivery systemsideally an asthma-type inhaler. Finally, researchers found no conclusive evidence that recommending marijuana medicinally would increase general use.
Proponents of medical marijuana cite scientific research indicating the potential therapeutic value of cannabinoid drugs, primarily THC, for pain relief, control of nausea and vomiting, and appetite loss that often accompany cancer and AIDS. However, proponents lament the fact that the emphasis on pharmaceutical research will delay treatment because research and development for new drugs can cost $300 million and only about one in five are approved.
In 1985, the U.S. Food and Drug Administration approved Marinol, a capsule containing THC, as a prescription drug. However, Marinol takes from one to several hours to take effect and many patients experience severe side effects. Since 1996, voters in Arizona, California, Oregon, several other states, and the District of Columbia have passed laws allowing medical use of marijuana.
Opponents focus their arguments on marijuana's addictive potential and other health problems.
Because marijuana is a crude THC delivery system that also delivers harmful substances, smoked marijuana should generally not be recommended for medical use. Nevertheless, marijuana is widely used by certain patient groups, which raises both safety and efficacy issues. Marijuana's future as a medicine lies in its isolated components, the cannabinoids and their synthetic derivatives. Isolated cannabinoids provide more reliable effects than crude plant mixtures.
The accumulated data suggest a variety of indications, particularly for pain relief, antiemesis, and appetite stimulation. For patients such as those with AIDS or who are undergoing chemotherapy, and who suffer simultaneously from severe pain, nausea, and appetite loss, cannabinoid drugs might offer broad-spectrum relief not found in any other single medication. The therapeutic effects of cannabinoids are most well established for THC, marijuana's primary psychoactive ingredient. Although marijuana smoke delivers THC and other cannabinoids it also delivers harmful substances, including most of those found in tobacco smoke. In addition, plants contain a variable mixture of biologically active compounds and cannot be expected to provide a precisely defined drug effect. For those reasons there seems to be little future in smoked marijuana as a medically approved medication.
While clinical trials are the route to developing approved medications, they are also valuable for other reasons. For example, the personal medical use of smoked marijuana to treat certain symptoms is sufficient reason to advocate clinical trials to assess the degree to which the symptoms or course of diseases are affected. Trials testing the safety and efficacy of marijuana use are an important component to understanding the course of a disease, particularly diseases such as AIDS. The argument against the future of smoked marijuana for treating any condition is not that there is no reason to predict efficacy but that there is risk. That risk could be overcome by the development of a non-smoked rapid-onset delivery system for cannabinoid drugs.
In addition to smoking, there are other means of cannabinoid delivery. Inhalers eliminate smoke toxicity while maintaining quick bloodstream entry. Pills are legal and smokeless, however, they can take over an hour to enter bloodstream and some patients cannot tolerate the concentrated dose.
The psychological effects of cannabinoids, such as anxiety reduction, sedation, and euphoria can influence their potential therapeutic value. Those effects are potentially undesirable for certain patients, although they may be beneficial for others. In addition, marijuana's psychological effects can complicate the interpretation of other aspects of the drug's effect.
Since marijuana smoke contains many of tobacco smoke's harmful components, it is important to consider the relationship between habitual marijuana smoking and lung disease. Given a cigarette of comparable weight, as much as four times the amount of tar can be deposited in the lungs of marijuana smokers as in the lungs of tobacco smokers. Marijuana smoke's carcinogenicity is an important concern.
Alveolar macrophages protect lungs against infectious microorganisms, inhaled foreign substances, and tumor cells. Marijuana smoking reduces the ability of alveolar macrophages to kill fungi, pathogenic bacteria, and tumor target cells. The reduction in ability to destroy fungal organisms is similar to that observed in tobacco smokers.
Marijuana smoke and oral THC can cause tachycardia (fast heart beat). In some cases blood pressure increases while a person is in a reclining position but decreases inordinately on standing, resulting in postural hypotension or decreased blood pressure, which may cause dizziness and faintness.
Advances in cannabinoid science have revealed a wealth of new opportunities for the development of medically useful cannabinoid-based drugs. The accumulated data suggest a variety of indications, particularly for pain relief, antiemesis, and appetite stimulation. For patients such as those with AIDS or who are undergoing chemotherapy, and who suffer simultaneously from severe pain, nausea, and appetite loss, cannabinoid drugs might offer broad-spectrum relief not found in any other single medication.
The risks of smoking marijuana should be considered before recommending its use to any patient with preexisting immune deficits, including AIDS patients, cancer patients, and those receiving immunosuppressive therapies.
The argument against the future of smoked marijuana for treating any condition is not the absence of efficacy but the risk. That risk could be overcome by the development of a non-smoked, rapid-onset delivery system for cannabinoid drugs.
Gabriel N., Sutin, K., and Harvey, D., eds. Marijuana and Medicine. Humana Press, 1999.
Joy J., Watson, S., and Benson, J., eds. Marijuana and Medicine: Assessing the Science Base. Institute of Medicine, 1999.
Mack, A. and Joy, J. Marijuana As Medicine?: The Science Beyond the Controversy. National Academy Press, 2000.
Kalb, C., Wingert, P., Rosenberg, D., Underwood, A., and Hammer, J. "No Green Light Yet: A long-awaited report supports medical marijuana. So now what?" Newsweek Section: Nation; Subsection: Medicine (March 29, 1999):35.
Sohn, E. "Is grass a proven tonic?" U.S. News & World Report (May 28, 2001).
Campaign to Legalise Cannabis International Association. Cannabis Campaigner's Guide, Up-to-Date Chronology of Cannabis Hemp. <<a href="http://www.paston.com.uk/uses/webbooks/chronol.html">http://www.paston.com.uk/uses/webbooks/chronol.html>.
Center for Cardiovascular Education, Inc. Smoking Marijuana Increases Heart Attack Risk. Heart Information Network. <<a href="http://www.heartinfo.org/news2000/marijuana061400.htm">http://www.heartinfo.org/news2000/marijuana061400.htm>.
Bill Asenjo, Ph.D., C.R.C.
Marijuana (Encyclopedia of Public Health)
Marijuana is a dried mixture of the leaves and flowers of Cannabis sativa, or hemp plant. Slang words for marijuana include "pot," "weed," "grass," and "dope." The term "cannabis" refers to different psychoactive preparations of the plant, including marijuana, hashish, and hashish oil. Hashish is the resin produced by the flowering tops of the plants; hashish oil is a concentrated form of cannabis extracted from the plant or resin using a solvent. Unpollinated female plants are called sinsemilla (sen-suh-mee-ah) and the flowering tops of these plants produce potent "buds" that do not contain seeds.
The major psychoactive ingredient in cannabis is delta-9-tetrahydrocannabinol (THC), but there are more than sixty related chemicals in marijuana, which are called "cannabinoids." Cannabis also contains other unrelated compounds that have similar psychoactive effects. The World Health Organization reported in 1997 that THC content in marijuana ranges from 0.5 to 4 percent, while concentrations in cannabis oil, hashish, and sinsemilla generally range from 7 to 14 percent, but may be as high as 20 percent. THC concentration depends on the variety, sex, and growing conditions of the plant, and it has increased over the years due to hydroponic cultivation techniques and selective breeding.
Marijuana and other cannabis products are usually smoked as a cigarette (a "joint") or in pipes, but may also be ingested orally. In the 1990s, the use of "blunts" to smoke marijuana became more common. A blunt is made by removing the tobacco from a cigar wrapper and filling it with marijuana, or a mixture of marijuana and some other drug like cocaine.
PSYCHOACTIVE AND PHYSIOLOGICAL EFFECTS
THC is absorbed more quickly into the bloodstream when smoked than when eaten. Effects are felt almost immediately and peak within thirty minutes of smoking. The marijuana "high" results when the THC binds with cannabinoid receptors in the brain. This process slows down regular nerve transmission, interfering with normal function. The cannabinoid receptors are located in the areas of the brain involved in muscle control, sexual functioning, vision and hearing, reasoning, hormone release, and memory.
Short-term effects include a temporary increase in heart rate, blood pressure, and blood flow to parts of the brain. Users generally feel a sense of euphoria, relaxation, hilarity, and heightened sensory perception. Negative psychological reactions may include anxiety, hallucinations, and panic attacks. Many smokers report that they feel unmotivated when they are high. Cannabis intoxication alters perceptions of time and space and impairs reaction timeffecting the performance of psychomotor tasks such as driving, which increases the risk of motor vehicle accidents. Cannabis increases food intake, impairs learning capabilities, and affects short-term memory. Many cannabis effects are subjective and influenced by the social circumstances, but the extent of impairment mainly depends on the potency and dose of the drug, the individual's tolerance to and experience using cannabis, and the difficulty and complexity of the task at hand.
LONG-TERM HEALTH CONSEQUENCES
Many of the studies done on the health consequences of marijuana have been inconclusive, although a picture is emerging of some worrisome long-term health effects. Smoking marijuana affects the respiratory system in much the same way as cigarette smoking. Cannabis smoke contains many of the same toxic chemicals and carcinogens as tobacco, as well as cannabinoids, all of which are respiratory irritants. Frequent marijuana smokers often report laryngitis, hoarseness, and coughing, and they are more likely than infrequent or nonusers to get acute and chronic bronchitis.
In a comprehensive analysis of the health effects of cannabis, the World Health Organization reports that cannabis is known to have adverse effects on the immune system, reproductive system, adrenal hormones, growth hormone, and cognitive function, particularly related to attention and memory processes. The long-term consequences of these effects, however, are not fully known, and further research is warranted. Smoking marijuana during pregnancy reduces oxygen flow to the fetus, which may interfere with growth and result in low birth weight, premature birth, and deficits in verbal ability and memory during childhood.
Preliminary research has demonstrated some positive health benefits of marijuana, including control of nausea and vomiting in people suffering from advanced cancer and AIDS (acquired immunodeficiency syndrome), appetite stimulation for those with wasting diseases, treatment of glaucoma by reducing intraoculer pressure, and control of convulsions and muscle spasms. More research in these areas is needed.
TRENDS IN MARIJUANA USE
Marijuana use by young people in North America peaked at the end of the 1970s, then declined progressively until the early 1990s, when use began to rise again. In the United States, it appears that the rate of increase may have stabilized at the end of the 1990s, although this stabilization was not apparent in Canada. The Monitoring the Future Survey found that lifetime use of marijuana among U.S. high school seniors peaked in 1979 at 60.4 percent, declined to a low of 32.6 percent in 1992, then rose to 49.6 percent in 1997, where it appears to have leveled off. A 1998 Canadian study on marijuana use did not report use among twelfth graders, but did find that approximately 42 percent of tenth graders had used marijuana in the previous year, up from 25 percent in 1991. In comparison, in 1998 only 31.1 percent of tenth graders in U.S. high schools reported use.
Marijuana use across the entire U.S. population was examined in a household survey in 1992 by the National Institute on Drug Abuse, which reported that 33 percent of Americans age 12 years and over had tried marijuana, 9 percent had used it during the previous year, and approximately 4 percent were current users, though the rate of use varied with age. These figures changed little in the 1998 survey. The proportion of Americans who reported having used marijuana at some point in their life was 11 percent among those 12 to 17 years old, 59 percent among those 26 to 34 years old, and 25 percent among people 35 years old and older.
1n 1994, the Canada Alcohol and Other Drug Survey found that 28 percent of Canadians had used cannabis at least once, 7.4 percent used it in the past year, and 3.2 percent were current users. During the early to mid-1990s, the proportion of people in other countries who reported having tried marijuana was 34 percent in Australia, 43 percent in New Zealand, 37 percent in Denmark, 17 percent in Switzerland and 14 percent in the United Kingdom. In general, marijuana use is lower among European, African, Asian, and South American youth than among young people in North America.
Different subgroups in the North American population report different rates of use. In general, males and white youth report higher rates of marijuana use than females, black youth, or young people from other racial or ethnic backgrounds. Young people who have dropped out of school are more likely to use cannabis than those who are in school, and 84.5 percent of students who attended alternative high schools in 1998 said they had tried cannabis.
MARIJUANA AND SUBSTANCE ABUSE
Since the 1970s, research has consistently demonstrated that adolescents progress through a uniform sequence of drug use involvement that begins with alcohol, cigarettes, and marijuana and proceeds to the use of "hard" drugs like hallucinogens, benzodiazepenes, amphetamines, sedatives, cocaine, and heroin. For this reason, marijuana, alcohol, and tobacco have been called "gateway" drugs. Some studies have shown that use of marijuana is almost a necessary condition for cocaine use by youth. The more frequently and intensively that gateway drugs are used, the greater the likelihood of dependence on the drug and progression to a later stage in the sequence of substance use involvement. However, most young people who use marijuana do not progress to dependence, or use harder drugs. The majority of marijuana users do not use other illicit drugs, although they are more likely to smoke cigarettes and drink alcohol than nonusers. Heavy use of marijuana does, however, place users in contact with more diverse networks of drug users and sellers, thereby increasing their exposure to other drugs and to the influence of those who use them. Participation in street culture is related to marijuana use. Those young people who do progress to abuse other illicit drugs and who experience the most harmful consequences are more likely to be socially and economically disadvantaged.
Most cannabis-use prevention programs are school based, and they tend to focus on illicit drugs in general, not just marijuana. The existence of a stable pattern of drug use suggests that prevention efforts should be directed not only at preventing the initiation of use, but also at curbing the transitions from experimental to regular use of any of the gateway drugs and the transition to other drugs. In reviewing what works in drug-use prevention, D. R. Gerstein and L. W. Green found that no prevention programs were reliably effective in all cases with all groups. However, a number of principles for effective prevention have been identified. The U.S. National Institute on Drug Abuse suggests that programs should be comprehensive and long-term, with reinforcement over several years; should target all forms of drug abuse; focus on the family, with a parent or caregiver component; include interactive methods, and be age-specific, developmentally appropriate, and culturally sensitive. School programs are best offered in the sixth through tenth grade, and should include components to develop interpersonal social skills, resistance skills, and self-efficacy, and to improve knowledge of health effects. The higher the level of risk in the specific population, the more intensive and targeted the program should be.
MARJORIE A. MACDONALD
(SEE ALSO: Addiction and Habituation; Behavior, Health-Related; Health Promotion and Education; School Health; Social Determinants; Substance Abuse, Definition of)
Adlaf, E. M.; Ivis, F. J.; Smart, R. G.; and Walsh, G. W. (1995). The Ontario Student Drug Use Survey: 1977995. Toronto: Addiction Research Foundation of Ontario.
Ellickson, P. L.; Hays, R. D.; and Bell, R. M. (1992). "Stepping Through the Drug Use Sequence: Longitudinal Scalogram Analysis of Initiation and Regular Use." Journal of Abnormal Psychology 101:44151.
Gerstein, D. R., and Green, L. W., eds. (1993). Preventing Drug Abuse: What Do We Know? Washington, DC: National Academy Press.
Grunbaum, J.; Kann, L.; Kinchen, S.; Ross, J. G.; Gowda, V. R.; Collins, J. L.; and Kolbe, L. J. (1998) "Youth Risk Behavior Surveillanceational Alternative High School Youth Risk Behavior Survey, United States, 1998." Morbidity and Mortality Weekly Report 48 (SS07):14. Available at .
Health Canada (1995). Canada's Alcohol and Other Drugs Survey: Preview 1995. Ottawa: Minister of Supply and Services Canada.
Howlett, A. C.; Bidautrussell, M.; Devane, W. A.; Melvin, L. S.; Johnson, M. R.; and Herkenham, M. (1990). "The Cannabinoid Receptoriochemical, Anatomical and Behavioral Characterization." Trends in Neuroscience 13(10):42023.
Johnston, L. D.; O'Malley, P. M.; and Bachman, J. G. (2000). The Monitoring the Future National Survey Results on Adolescent Drug Use: Overview of Key Findings, 1999 (NIH Publication No. 00690). Rockville, MD: National Institute on Drug Abuse.
Kandel, D. B. (1975). "Stages in Adolescent Involvement in Drug Use." Science 73:54352.
Kandel, D. B., and Yamaguchi, D. B. (1984). "Patterns of Drug Abuse from Adolescence to Early Adulthood:III. Predictor of Progression." American Journal of Public Health 74:67381.
King, A. J. C.; Boyce, W. F.; and King, M. A. (1999). Trends in the Health of Canadian Youth. Ottawa: Health Canada. Available at .
Kozel, N. (1997). Epidemiological Trends in Drug Abuse: Advance Report. Washington, DC: National Institute on Drug Abuse. Available at .
National Institute on Drug Abuse (1992). National Household Survey on Drug Abuse: Population Estimates 1992. Rockville, MD: National Institute on Drug Abuse.
(1999). National Household Survey on Drug Abuse, National Estimates of Substance Use, 1999. Bethesda, MD: Substance Abuse and Mental Health Services, National Institute on Drug Abuse. Available at http://www.samhsa.gov/OAS/NHSDA/1999/.
World Health Organization (1997). Cannabis: A Health Perspective and a Research Agenda. Geneva: WHO, Division of Mental Health and Prevention of Substance Abuse.
Marijuana (Encyclopedia of Drugs and Addictive Substances)
- What Is It Made Of?
- How Is It Taken?
- Montel Williams on Medical Marijuana
- Effects on the Body
- Treatment for Habitual Users
- The Law
- For More Information
What Kind of Drug Is It?
Marijuana is the most widely used illegal controlled substance in the world. Although the drug has been illegal in the United States since the 1930s, an estimated 40.6 percent of the U.S. population over twelve years of age (forty out of every one hundred people) has tried it at least once. As recently as 2003, 25.2 million peopleasically one in ten Americanseported using the drug at least once that year, as reported by the Office of National Drug Control Policy.
Marijuana, or the plant Cannabis sativa, has been used as a medicine, as a part of religious ceremonies, and even as a fiber for making clothing, rope, and paper for many thousands of years. It has also been used in many cultures, both ancient and modern. Still, its effects on the brain and body are not yet completely understood. Scientists differ on how to classify the drug: Is it a hallucinogen like LSD (lysergic acid diethylamide), a narcotic like opium, or does it belong in a class by itself? (Entries on LSD and opium are included in this encyclopedia.) To further confuse matters, some scientists call marijuana a stimulant, or a substance that makes the brain and body more active, and some call it a depressant, or a substance that slows down brain and body processes. Whatever its properties, organicA term used to describe chemical compounds that contain carbon.r plant-derivedarijuana is illegal to possess or sell as a recreational substance.
The controversy over marijuana's role as a medicine for certain illnesses highlights the drug's strange history in American society. A small minority of Americans wants the drug to be made legal and sold under controlled circumstances, similar to the sale of alcohol. The U.S. government has made no move to legalize marijuana possession and, in fact, has tightened laws against it since the 1980s. People who buy, sell, or use marijuana for recreational purposes face many penalties if caught, including a permanent criminal record.
The earliest archeological evidence of marijuana comes from China. Twelve thousand years ago the plant was cultivated there for many uses. Its fibers, known as , could be woven into
sturdy clothing or rope, or even processed as paper. The Chinese also used the plant as a medicine for anxiety and physical pain. From China the use of the plant spread to India, where by 2000 BCE it had become part of religious ceremonies. The Vedas, a series of Indian religious writings, credits the god Shiva with introducing cannabis to humankind, to help relieve the soul from suffering. To this day, a mild marijuana preparation called bhang is used during holidays in India, just like Americans might toast in the New Year with champagne.
An Ancient History
In his book Illegal Drugs: A Complete Guide to Their History, Chemistry, Use and Abuse, Paul M. Gahlinger noted that Europeans had discovered and were using cannabis by the fifth century BCE. By the time Venetian traveler Marco Polo (c. 1254324) made his famous expedition to the Far East in the late thirteenth century, the drug was widespread throughout the Middle East, Asia, Europe, and Africa.
Different cultures used it in varied ways even then. Marco Polo records the legend of the "Old Man of the Mountain," a Muslim Middle Easterner said to have recruited assassins by intoxicating them with hashishConcentrated, solidified cannabis resin., which is the solidified form of the drug. (The very word "assassin" is said to have roots in "hashish," but the story Marco Polo reports has never been verified.) In Europe as early as the Middle Ages (c. 500. 1500), hemp was planted for use as clothing and rope, and cannabis was used as medicine for illnesses as varied as menstrual cramps, labor pains, and headaches. Its recreational uses were understood as well, and in 1484 Pope Innocent VIII (1432492) said that hashish consumption was linked to Satanic rituals.
Grown on Plantations
As cannabis fell out of favor as a recreational drug, it grew in importance as a plant fiber. The era of exploring the world by sailing ship had dawned, and demand for canvasnother word derived from cannabisrew rapidly. In 1533, King Henry VIII (1491547) commanded all English farmers to set aside part of their holdings to grow hemp. The plant was exported to the Americas, where it was first grown in Canada in 1606 and in Virginia in 1611. In the United States, it was used for making canvas and rope. However, written documents note that George Washington (1732799), the first U.S. president, not only grew cannabis but also used it to soothe his toothaches. According to the 1850 U.S. Census, the plant was grown on 8,327 plantations in the nation.
The renewed interest in recreational use of cannabis dates to the 1840s, when Egyptian hashish spread among the artistic communities in France and England as a drug of enlightenment (enhanced intelligence). At the same time, the medical community in Europe renewed its interest in the substance, recommending it for a wide variety of ailments from asthma and depression to . Cannabis was also recommended to the mentally ill and to alcoholics and people with opium addiction. In the heyday of "cure-all" medicines during the early 1900s, marijuana extracts could be found in many over-the-counter remedies, sometimes mixed with opiates like morphine. (An entry for morphine is available in this encyclopedia.)
The Tide Turns
In time, the tide of American opinion turned against marijuana. Some historians credit business tycoon William Randolph Hearst (1863951) with launching this crusade. Hearst, who owned many major newspapers, also owned many thousands of acres of trees that he planned to turn into paper. As late as the 1880s, almost all American paper was made from hemp, and a great deal of hemp was still grown in the United States. (The U.S. Declaration of Independence was published on hemp paper.) Hearst capitalized on anti-Mexican prejudice and, through his newspapers, linked marijuana use to Mexican immigrants, crime, violent behavior, and poor job performance. It was the Hearst newspaper chain that changed the spelling of marijuana from its older form, marihuana. During this time, use of the word cannabis faded as well.
According to Hugh Downs, in a commentary for ABC News in 1990: "Nobody was afraid of hempt had been cultivated and processed into usable goods, and consumed as medicine, and burned in oil lamps, for hundreds of years. But after a campaign to discredit hemp in the Hearst newspapers, Americans became afraid of something called marijuana." Downs also noted that the crusade against hemp "misled the public into thinking that marijuana and hemp were different plants."
Hearst's campaign was one of many waged against marijuana in the 1930s. Another important figure who changed American attitudes toward the drug was Harry Anslinger (1892975), head of the Commission of Narcotics during the Great Depression (1929941). Bolstered by scientific studies published in credible journals, Anslinger was able to convince state governments that marijuana use caused an increase in crime and violence, that it was addictive, and that its attraction to young people could lead to a lifetime of trouble. Hollywood seemed to support this view, issuing a series of hour-long dramas about marijuana, of which Reefer Madness (1936) is the best known. In Reefer Madness and other similar films, young, innocent people become violent, dishonestr at least rather hystericalictims of the "devil weed."
Following a series of congressional hearings, the U.S. government passed the Marijuana Tax Act of 1937. The act did not outlaw marijuana outright, but "created a tax structure around the cultivation, distribution, sale, and purchase of cannabis products, which made it virtually impossible to have anything to do with the drug without breaking some part of the tax law," wrote Cynthia Kuhn and her coauthors in Buzzed: The Straight Facts about the Most Used and Abused Drugs from Alcohol to Ecstasy. In other words, the 1937 law made it impossible to reap a legal profit from growing cannabis.
After World War II (1939945), a new generation of young people began to frequent urban jazz clubs, where the musicians often used marijuana and other drugs. Interest in recreational marijuana increased. As the teenagers of the 1960s and 1970s began using the drug in record numbers, they showed that many of the "scientific" claims made against marijuana in the 1930s were untrue. Marijuana, it appeared, did not cause violence or hysterical behavior. It was not particularly addictive, and it appeared to have few lasting effects on the user in the days and weeks following a dose. This finding led various people to mistakenly doubt all information they had received about illegal drugs, based on their own experiences with marijuana. This created a climate of illegal drug experimentation that has lasted into the twenty-first century.
Such experimentation led to drugs flooding the and being sold illegally on the street.
Federal Government Labels Marijuana a Hazard
In 1970, the U.S. Controlled Substances Act named marijuana and its by-products, hashish and hash oil, as Schedule I controlled substances. This is the highest level of control, indicating a substance with a high probability of abuse and no medical benefit. Even in 1970 some members of the medical and scientific community felt that marijuana should not have been placed in the same category as drugs such as LSD and heroin. (Separate entries on LSD and heroin are available in this encyclopedia.)
By the end of the twentieth century, several medical uses for cannabis had been documented with full research evidence. These include being an appetite-enhancer in cancer and acquired immunodeficiency syndrome (AIDS)An infectious disease that destroys the body's immune system, leading to illness and death. patients; a pain reliever in patients; and a muscle relaxant for those suffering from multiple sclerosisA progressive illness that affects muscle tissue, leading to pain and inability to control body movements., a degenerative disease of the central nervous system.
Chemists developed a synthetic (laboratory-made) tablet, dronabinol (manufactured as Marinol), that contains one of the chemicals found in marijuana. Dronabinol was introduced in 1985 as a Schedule II substance and has since been placed in the Schedule III category, making it as easy to prescribe as codeine. (An entry on codeine is available in this encyclopedia.) Still, some patients found that the dronabinol pills did not work as well as smoking cannabis.
Gonzalez v. Raich
By 2005, ten states had passed "medicinal marijuana" bills, allowing people with certain illnesses to grow or obtain enough marijuana for their own use. But these state laws for medical marijuana conflict with the federal laws against its possession. Late in 2004, two California women brought their petition for medical marijuana to the U.S. Supreme Court.
The Supreme Court case that concerned state laws on medical marijuana use, called Gonzalez v. Raich, was decided on June 6, 2005. The Supreme Court ruled 6-3 that Congress has the authority to prohibit the local cultivation of marijuana, even if it is used for medical marijuana, under federal interstate commerce laws. Under federal law, people in states that permit medical marijuana use will not be able to buy the plant form of marijuana or to grow it for their own consumption legally.
After the ruling on June 6, Oregon stopped issuing medical marijuana cards, given to patients with a doctor's prescription through the Oregon Medical Marijuana Program. However, the state continued to process applications. On June 17, 2005, Oregon's attorney general, Hardy Myers, stated that the program would begin issuing the medical marijuana cards again because the Supreme Court ruling did not affect the state's program. Myers did make it clear that though people using medical marijuana through Oregon's program will not be violating state laws, users could still be arrested and prosecuted by the federal government. In addition, Myers said that the state cannot protect patients' caregivers and those growing medical marijuana plants should the federal government decide to prosecute them.
What Is It Made Of?
Marijuana comes from two plants that are so closely related they are probably the same species. The plants are Cannabis sativa (marijuana/hemp), and Cannabis indica, a bushier variety grown simply for its psychoactive (brain-altering) qualities. Cannabis produces male and female plants, and both of them contain delta-9-tetrahydrocannabinol or , the main mind-altering chemical in marijuana. Female plants, especially those that are not allowed to pollinate, or fertilize another plant, contain the highest concentrations of THC.
Marijuana smoke contains sixty-one different chemical compounds, called cannabinoidsChemical compounds found in cannabis plants and in small amounts in the brains of humans and animals., that are unique to the plant. Scientists are not sure exactly how these compounds interact with THC to produce the effects associated with a marijuana high. They do know that the most important mind-altering compound in cannabis is THC.
The cannabinoid compounds in marijuana can be found throughout the plantn the leaves and stems, for instance. But the strongest concentrations of THC and other cannabinoids are found in the buds and flowering tops of the female plants. The time of harvest determines the amount of THC in the buds. Female plants that are kept away from male plants will not pollinate and produce seeds. Instead they keep producing flowers that contain a powerful resinhe plant's signal that it wants to pollinate. These resinous buds are the strongest form of marijuana, called (the Spanish term for "without seeds").
Purchased on the street, marijuana and sinsemilla are green or brown buds, leaves, or stems. The leaves and stems do not contain the concentrations of THC found in the buds and flowers, but people smoke them to get high.
Hashish is another product of the cannabis plant. It consists of the dried resin from the flower buds and is also very high in THC content. The resin is gathered by hand from the cannabis buds and rolled into gummy balls. Once a quantity of the balls has been collected, they are pressed together into larger cakes or sheets that resemble dark-colored dough. A highly powerful product, hash oil, is produced by boiling hashish or marijuana in a liquid that absorbs THC, such as alcohol, gasoline, or kerosene. The remaining plant material is filtered out, leaving behind thick oil. The color varies from clear to black, with yellows and browns in between. Hash oil contains the highest concentrations of THC. Just a drop or two on an ordinary tobacco cigarette will have an effect similar to smoking a whole dose of marijuana.
Marijuana is grown throughout the United States, even though it is illegal. It is rare to find a state forest or national park anywhere
that has not been put to use by anonymous growers. Still, the bulk of the marijuana bought on America's streets comes from Mexico andncreasinglyanada, where it is grown indoors under ideal conditions.
Hashish also arrives in the United States from Pakistan, Nepal, Afghanistan, and the Middle East. Since it is a federal crime to bring these drugs across U.S. borders, smugglers find many alternative ways to deliver the product into dealers' hands. Most of the Mexican marijuana that arrives in America comes by car or truck, hidden among legal products or even within the upholstery of a vehicle. One group of smugglers got caught trying to bring marijuana into Texas inside coffins.
How Is It Taken?
In order to produce psychoactive effects, marijuana must be heated. People cannot get high just by eating the raw plant material, unless they eat hashish or buds with the highest concentration of THC. Even so, the high produced will be lessened and will establish itself slowly, over a period of hours. Marijuana does not dissolve in water or other room-temperature solvents, so it cannot be injected.
The most common way to use marijuana is to smoke it. Small amounts of marijuana are rolled into cigarette papers and smoked. These are called "spliffs" or "joints." Pipes are also used, both the conventional sort that are made for tobacco and special ones just for marijuana or hashish. More elaborate pipes, called "bongs," pass the smoke through water as the user inhales. Bongs work with tobacco as well as marijuana, but vendors who sell them still run the risk of getting arrested for peddling drug paraphernalia (items used to deliver drugs into the system). Users also hollow out cigars and replace the tobacco with marijuana. These are called "blunts."
Marijuana, or more often hashish, is also baked into food, such as "hash brownies." The cooking process releases the same chemicals that are released while smoking. When eaten, baked hashish products can provide the strongestnd most unpredictableigh. Some users brew marijuana as a tea as well.
Are There Any Medical Reasons for Taking This Substance?
The U.S. government lists marijuana and its by-products as Schedule I substances, indicating that cannabis has no medical value. However, since the 1970s, marijuana has been used as a medicine for several specific conditions, although the legality of this use remains under debate.
Cancer patients who receive , the use of chemicals to prevent or treat the disease, often suffer the side effects of nausea, vomiting, and loss of appetite. This can cause people who are already sick to lose weight and become more prone to secondary illnesses. Marijuana stimulates the appetite. Chemotherapy patients who use it are more likely to maintain body weight and suffer less from nausea.
The scientific evidence for these claims has led chemists to create a synthetic form of THC, taken as a pill called Marinol. However, the pills seem to have less effect than smoking the drug. Perhaps this is due to the fact that the pills have to be swallowed and digested, and this can be a problem for cancer sufferers. (Some cancer patients take
Marinol pills prior to chemotherapy.) Also, the pills contain THC, but not the other cannabinoids. Most scientists believe that THC alone does not account for the appetite-enhancing qualities of marijuana.
Marijuanand Marinolre also used to enhance the appetite in patients suffering from acquired immunodeficiency syndrome (AIDS). People with AIDS sometimes "waste away" from lack of appetite. Maintaining nutrition can help them stay strong to fight infection. Again, doctors can prescribe Marinol, but the Schedule III drug is not as effective as smoked marijuana.
Evidence suggests that marijuana eases the pain and the symptoms of multiple sclerosis, a progressive disease that affects the muscles. It is also used for a disease of the eyes called glaucoma, where it helps to relieve painful pressure in the eye tissue.
Although it is not prescribed or indicated for use in depression or anxiety, marijuana has been used as a medication for those illnesses in the past. It is unlikely to be re-introduced for this use, however, given the number of modern prescription medications that exist for depression and anxiety.
State vs. Federal Government
The several uses for marijuana as medicine have led some states to pass "medical marijuana" laws. Such laws allow patients with proven medical conditions to possess a small amount of marijuana without facing criminal penalties. These state laws openly contradict the federal law that makes possession of marijuana for any use a crime.
In 2005, a case based on this contradiction was heard by the U.S. Supreme Court. The federal government gained a limited victory in this case on June 6, 2005. The court decided that the federal government could prosecute patients for personal possession and cultivation of marijuana despite state medical marijuana laws. Yet the court did not overturn state medical marijuana laws. This means that although it is a federal crime to possess or grow marijuana, it is not a state crime in those states where medical marijuana has been made legal. According to CNN.com, "along with California, nine [other] states have passed laws permitting marijuana use by patients with a doctor's approval: Alaska, Colorado, Hawaii, Maine, Montana, Nevada, Oregon, Vermontand Washington. Arizona also has a similar law, but no formal program in place to administer prescription pot."
Chemists and pharmaceutical companies continue to research delivery systems for marijuana that will be considered legal (if covered by a prescription), including inhalers similar to those used by people suffering from asthma.
Four in ten Americans have used marijuana at least once in their lifetimes. One in ten Americans reports using the drug at least once in the past year, and six in every one hundred Americans report using the drug at least once in the past month. These statistics come from the "2003 National Survey on Drug Use and Health (NSDUH)." According to the NSDUH report, 96.6 million Americans have tried marijuana at least once.
The 1999 "National Household Survey on Drug Abuse" reported that the age group least likely to have tried marijuana is people over seventy. The group most likely to have tried it is eighteen- to twenty-five-year-olds. A Youth Risk Behavior Surveillance System survey conducted in 2001 indicated that 23.9 percent, or just over two in ten people between the ages of ten and twenty-four, had used marijuana in the month before the survey took place. The 2001 survey reported that males were more likely to smoke marijuana than females, but the 2003 NSDUH report said that 53 percent of first-time marijuana users were female. The only large group showing less first-time use of marijuana was Asian Americans. Otherwise the drug is equally popular among African Americans, Caucasians, Native Americans, and Hispanic Americans.
In the 2004 Monitoring the Future study, 16.3 percent of eighth graders, 35.1 percent of tenth graders, and 45.7 percent of twelfth graders reported using marijuana at least once. And despite major efforts to find and punish dealers, 73.3 percent of tenth graders and 85.8 percent of twelfth graders noted that marijuana is "fairly easy" or "very easy" to obtain. Clearly, it is nearly impossible to pass through high school without meeting at least one person who uses or sells marijuana.
Although the U.S. government has maintained a policy of strong opposition to marijuana use, the drug has found an appeal across generations. People attending high school in the early part of the twenty-first century are more likely to have parents who tried marijuana than people who attended high school in the 1950s or 1960s. This translates to a more tolerant attitude among some parents toward marijuana use in their children. Nevertheless, the 2003 NSDUH survey did find that lifetime use of marijuana is declining among teens.
Effects on the Body
The human brain contains , specifically for cannabinoids. The brain also produces its own natural cannabinoids, called anandamide (uh-NANN-duh-myd) and 2-arachidonylglycerol (AH-ruh-kid-ON-uhl-GLISS-uh-rol). These two compounds have been found in the brains of animals as well.
What Happens in the Brain
All of the cannabinoid receptors are located in the brain. There are no cannabinoid receptors in the spinal column, so using marijuana does not affect a person's ability to breathe or the function of other organs in the body.
When marijuana is smoked, THC and the other cannabinoids flow to the brain from the lungs, where the compounds are transferred into the bloodstream. The effects begin within minutes, generally with a feeling of light-headedness and euphoria (intense happiness). The user may become less inhibited, more outgoing, and laugh easily. At the same time, the user can experience a loss of motor control and difficulty concentrating. Since most of the cannabinoid receptors are located in the hippocampusA part of the brain that is involved in learning and memory., the center of memory and learning, people high on marijuana have difficulty learning new things or remembering what is happening at the moment. Marijuana does not destroy memories that already exist before the user gets high.
The typical marijuana experience is one of euphoria, heightened sensations of music and light, relaxation, and increased appetite. Sometimes, however, even the most experienced users will react differently. The drug can heighten anxiety and create n uncomfortable feeling of danger or distress. When that happens, the user can do little but ride out the unpleasant experience, which usually happens within two to three hours.
The marijuana high gradually changes to a period of diminished physical activity and communication. The term "stoned" was coined to describe this period. In two to six hours the cannabinoid overload begins to exit the brain, usually causing a spike in appetite along the way. When users get hungry, they are said to have "the munchies."
It is not possible to smoke a fatal dose of marijuana. It is possible to consume too much THC by eating baked goods with hashish in them. Still this does not lead to death, but rather to a possibly unpleasant "trip" with paranoid or psychotic (extremely frightening) episodes. Again, no antidote to cannabis exists except trying to get the victim to vomit the undigested portion of the baked goods.
Effects on Judgment, Memory, and Learning
There is no such thing as a safe recreational drug. A person high on marijuana has the same lack of judgment, poor coordination, and diminished sense of fear as a person drunk on whiskey. The leading cause of death for young people is automobile crashesnd sometimes those fatal crashes are caused by marijuana, or a combination of marijuana and other drugs or alcohol. Marijuana impairs the ability to drive, operate machinery, or judge dangerous situations. As such, it can be deadly.
Because marijuana affects memory and learning, daily use can undermine a student's ability in school or a worker's capability on the job. Although scientists have debunked the old caution that marijuana affects motivation, the drug does affect short-term memory and the brain's ability to process new material. People who smoke marijuana regularly almost always experience declines in grades and difficulties in the classroom related to the drug use.
THC, the most active component of marijuana, remains in the body long after the psychoactive effects have worn off. The body stores THC in its fat cells. After one use, a person will test positive for THC for as many as three days. With regular use, a person can test positive for THC even after abstaining from marijuana for four weeks. The drug tests available at the turn of the twenty-first century were sophisticated enough that they do not yield a positive result for "passive" marijuana smoking (just being around other people who
are using the drug). Thus, law enforcement officers will not accept that as a defense. As Paul M. Gahlinger stated in his book, "If the drug test is positive for marijuana, the only legitimate excuse is either the use of dronabinol or, if allowed, the use of medically prescribed marijuana."
What Happens in the Lungs
Marijuana smoke contains the same cancer-causing compounds as tobacco, including tar, benzanthrene (ben-ZANN-threen), and benzpyrene (benz-PIE-reen). Since marijuana smokers inhale more deeplynd because joints, pipes, and blunts do not contain filtershe user exposes the lungs to more of the cancer-causing agents. Smoking marijuana daily or even occasionally for a period of years increases the risk of lung cancer. Smoking both marijuana and tobacco greatly increases that risk.
Link to Mental Illness?
A study released in 2005 by the Office of National Drug Control Policy found that people who begin smoking marijuana at a young ageetween ten and fourteenun a high risk of mental problems later in life. The study found that between 8 and 9 percent of the general population develop serious mental illnesses in adulthood. For people who begin using marijuana before the age of twelve, the chances of developing mental illness leap to 21 percent. Two reasons could account for this. First, marijuana could have a bad effect on the developing brain. Second, someone tempted to use marijuana at such a young age might already be predisposed to have emotional or psychological problems. Also, a significant percentage of heavy marijuana users may be "self-medicating" to treat a variety of mental conditions. These conditions include anxiety, phobias, or depression.
Withdrawal from marijuana is not terribly difficult, even after heavy use. The symptoms of marijuana withdrawal include insomnia, anxiety, decreased appetite, and irritability. Usually these symptoms go away within a few weeks if the user does not return to the drug.
A "Gateway Drug"?
For several decades marijuana has been described as a "gateway drug"ne that leads users to experiment with more dangerous, more addictive substances. That theory has been dismissed, however. Most people use marijuana and then stop taking any illegal drugs. Far fewer progress to other substances. So it could just as easily be said that marijuana is an "end stage" drug. Again, the individual person's mental makeup determines whether or not marijuana use will lead to harder drugs. People with family histories of mental problems, alcoholism, anxiety, or depression should try to avoid every psychoactive substance, including legal ones like alcohol and nicotine. (Entries for alcohol and nicotine are available in this encyclopedia.) For anxious or depressed people, better treatments exist than marijuana use.
Reactions with Other Drugs or Substances
One of the biggest problems with any illegal substance is the variation in quality. Some sources say that marijuana produced in the twenty-first century is far stronger than that smoked in previous decades. Others say the doses are about the same. Whatever the case, each purchase of illegal marijuana carries dangers related to the strength of the product, the possible by-products, and the methods of preparation. Outdoor-grown marijuana might have been sprayed with pesticides that still linger on the leaves and buds. The plants might also have fungus or even bacteria from the unclean hands that picked or packed them.
Dealers sell marijuana joints containing PCP, a hallucinogen, or crack cocaine. are joints dipped in formaldehyde, a chemical compound used as a preservative and disinfectant. All of these combinations have proven fatal in users. In November of 2004, the Newark Star-Ledger reported the death of a seventeen-year-old who ran naked across a busy highway and hurled himself through a glass window after smoking a fry stick. The young man died of the injuries he sustained from crashing through the glass.
Mixing marijuana and alcohol heightens the effects of each substance and can lead to reckless behavior. Mixing marijuana with amphetamines or even tobacco can increase the heart rate, possibly causing heart damage or stroke.
Treatment for Habitual Users
More people are treated in rehabilitation programs for marijuana use than for any other drug. This is partly because more people are arrested for marijuana possession and ordered into treatment by the courts. Whatever the case, marijuana usersven heavy marijuana usersan usually free themselves of the drug fairly easily if they have no history of other drug or alcohol abuse. The situation becomes more complicated when marijuana has been combined with other powerful drugs such as cocaine or an opiate, like heroin or morphine.
Some people do become physically addicted to marijuana and experience withdrawal symptoms when they stop using it. For most people, use is a psychological habit and is sometimes a form of self-treatment for anxiety, depression, phobias, panic attacks, or other serious mental illnesses. When people find themselves spending more time buying, smoking, and becoming stoned on the drug than they do studying, socializing with friends and family, or working, they should seriously consider getting professional help to stop their marijuana use. Such help includes examination by a medical doctor and therapy with a psychologist or psychiatrist who can help find the root causes and proper treatment for the drug abuse. Self-help twelve-step programs such as Narcotics Anonymous also provide opportunities to beat the drug with the help of others who have experienced similar addiction problems.
Buying, selling, and using recreational marijuana is illegal. Penalties for marijuana possession vary from state to state and from country to country. The penalties are often based on the amount of marijuana found; whether the person intended to sell the marijuana; and whether the person was intoxicated at the time of the arrest. However, even first-time marijuana convictions can wreck a life. For instance, someone convicted of marijuana possession will lose any federal financial aid they might be receiving to attend college. (In contrast, theft convictionerhaps of a laptopoes not automatically result in loss of financial aid.) In some states, employers are notified when someone is caught with marijuana. Almost half the states in the nation suspend the driver's license of anyone convicted of marijuana possession, though the length of the suspension varies from state to state and depends on the circumstances and number of offenses.
Judges usually sentence marijuana users to high fines, community service, and drug tests for up to a year, just with a first conviction. Second convictions, or possession with intent to sell, can land a person in jail. Judges can also order marijuana users into treatment programs. Whatever the penalties, the marijuana user has earned a criminal record that will impact future job opportunities, the ability to drive legally, and educational choices.
Legal consequences aside, long-term users of marijuana will find that it affects their ability to learn, remember, and concentrate. THC stays in the body long after the high has worn off, and it can continue to impact the brain. Additionally, some of the ingredients in a marijuana cigarette are known , or cancer-causing agents. People who smoke marijuana run a higher risk of lung cancer than those who do not.
Habitual use of marijuana can either mask or aggravate symptoms of mental illness. People prone to psychosisPronounced sy-KOH-sis; a severe mental disorder that often causes hallucinations and makes it difficult for people to distinguish what is real from what is imagined., a severe mental disorder, can have bad reactions to a marijuana high. People who are depressed or anxious may lean on the drug to ease their symptoms, rather than find the professional help they need for their illnesses.
By the end of 2004, ten American states had passed "medical marijuana" laws. The details of these laws vary from state to state, but they usually require a doctor's written prescription for marijuana use and documentation of the illness for which the marijuana is recommended. In some states, patients carry cards that identify them as medical marijuana users. These users must either grow their own plants or find a state-sanctioned grower who can prove that the marijuana is only grown for medical use, and only distributed within the boundaries of that state. Doctors who misidentify patients and permit medical marijuana use where it does not apply face criminal penalties.
On June 6, 2005, the U.S. Supreme Court ruled that under federal law, even in states where "medical marijuana" laws existed, all use of medical marijuana was illegal. Yet later that month, Hardy Myers, Oregon's attorney general, said that under Oregon state law, medical marijuana cultivation and medical use was still legal. This meant that the state would not prosecute growers and users of medical marijuana, but that the federal government could, and the state could not offer protection against the federal laws.
All other use of marijuana in all states is considered a crime. Some states have very stiff penalties even for first-time users. Other states allow first-time users to pay fines and undergo drug testing and counseling. In New Jersey, for instance, the 2003 penalty for a first arrest on marijuana possession was $1,000 and a year of drug testing. Students caught with marijuana lose any federal financial aid they might be receiving for college. If still in high school, the student will not qualify for federal financial aid.
Because marijuana is such a popular recreational drug, federal and state prisons are full of people who have been caught dealing it. Sometimes these dealers face longer jail terms than people convicted of armed robbery or manslaughter. Repeat offenders can be sent to jail for life.
For More Information
Earleywine, Mitch. Understanding Marijuana: A New Look at the Scientific Evidence. New York: Oxford University Press, 2002.
Gahlinger, Paul M. Illegal Drugs: A Complete Guide to Their History, Chemistry, Use and Abuse. Las Vegas, NV: Sagebrush Press, 2001.
Kuhn, Cynthia, Scott Swartzwelder, and Wilkie Wilson. Buzzed: The Straight Facts about the Most Used and Abused Drugs from Alcohol to Ecstasy, 2nd ed. New York: W.W. Norton Company, 2003.
Zimmer, Lynn, and John P. Morgan. Marijuana Myths, Marijuana Facts: A Review of the Scientific Evidence. New York: The Lindesmith Center, 1997.
Agar, John. "Driver Sent to Prison for Teen's Death." Grand Rapids Press (January 22, 2005): p. 3.
Bauer, Jeff. "Marijuana Abuse and Dependence Is on the Rise." RN (July, 2004), p. 18.
"Counseling to Prevent Motor Vehicle Injuries." American Family Physician (May, 1990), p. 1465.
"Employee's Use of Medical Marijuana May Justify Dismissal." Fair Employment Practices Guidelines (February, 2005), p. 6.
Gluck, Gabriel H. "Police Test for Drugs after Teen's Death: Laced Marijuana Possible in Mountainside Incident." Star-Ledger (November 12, 2004), p. 29.
Greenburg, Jan Crawford. "Supreme Court Hears Arguments on Medical Marijuana Use." Chicago Tribune (November 30, 2004).
Klein, Naomi. "Canada: Hippie Nation?" The Nation (July 21, 2003), p. 12.
"Not So Dopey: Marijuana as Medicine." The Economist (April 9, 2005), p. 69.
"Researchers Say Marijuana Addiction Is Up." UPI News Track (May 5, 2004).
Richey, Warren. "Showdown over Medical Marijuana: The Supreme Court Hears a California Case Monday That Could Become a Signature Decision of the Rehnquist Era." Christian Science Monitor (November 29, 2004), p. 2.
Salooja, Anjali. "A New Generation of Lollipops." Newsweek (July 18, 2005): p. 12.
Williams, Montel. "Turning Patients into Criminals." Cincinnati Post (April 11, 2005), p. A10.
"Youth Risk Behavior Surveillance: United States, 2001." Journal of School Health (October, 2002), p. 313.
"2003 National Survey on Drug Use and Health (NSDUH)." Substance Abuse and Mental Health Services Administration (SAMHSA). http://www.drugabusestatistics.samhsa.gov (accessed July 29, 2005).
"Admissions to Treatment for Marijuana Abuse Increase Sharply" (March 4, 2005). U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration. http://www.samhsa.gov/news/newsreleases/050304nr_mjtx.htm (accessed July 29, 2005).
"Attorney General Issues Advice on Medical Marijuana Program" (June 17, 2005). State of Oregon, Department of Justice. (accessed July 30, 2005).
"Catholic Encyclopedia: Marco Polo." Catholic Encyclopedia. http://www.newadvent.org/cathen/12217a.htm (accessed July 29, 2005).
"Cops Find 610 Pounds of Pot in Coffins." USA Today, December 16, 2004. http://www.usatoday.com/news/offbeat/2004-12-16-caskets_x.h... (accessed July 29, 2005).
Courson, Paul. "Research: Youth Risks Mental Health with Pot Use." CNN.com, May 3, 2005. http://www.cnn.com/2005/HEALTH/05/03/pot.risk/ (accessed August 1, 2005).
Frieden, Terry. "Drug Tunnel Found Under Canada Border." CNN.com, July 22, 2005. http://www.cnn.com/2005/US/07/21/border.tunnel/index.html (accessed August 1, 2005).
Johnson, Gene. "Feds Shut Down Drug-Smuggling Tunnel." Washington-Post.com, July 22, 2005. (accessed August 1, 2005).
"The Link Between Marijuana and Mental Illness" (May 5, 2005). Office of National Drug Control Policy, Executive Office of the President. http://www.mediacampaign.org/pdf/marij_mhealth.pdf (accessed August 2, 2005.
"Marijuana." Office of National Drug Control Policy. http://www.whitehousedrugpolicy.gov/drugfact/marijuana/inde... (accessed July 29, 2005).
"Marijuana May Increase Risk of Psychosis." MSNBC.com, December 1, 2004. http://www.msnbc.msn.com/id/6629828/ (accessed July 29, 2005).
Mears, Bill. "Supreme Court Allows Prosecution of Medical Marijuana." CNN.com, June 7, 2005. http://www.CNN.com/2005/LAW/06/06/scotus.medical.marijuana/ (accessed July 28, 2005).
"Media Campaign Fact Sheets: Marijuana and Mental Health." Office of National Drug Control Policy, National Youth Anti-Drug Media Campaign. http://www.mediacampaign.org/newsroom/factsheets/marij_mhea... (accessed August 1, 2005).
Monitoring the Future. http://www.monitoringthefuture.org/ and http://www.nida.nih.gov/Newsroom/04/2004MTFDrug.pdf (both accessed August 31, 2005).
"National Household Survey on Drug Abuse: 1999." U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration. http://www.samhsa.gov/news/newsreleases/000831nrhousehold.h... (accessed August 1, 2005).
"Oregon Resumes Issuing Medical Marijuana Cards." NorthWest Cable News, June 17, 2005. (accessed July 30, 2005).
"Pot-Flavored Candy Takes a Licking." MSNBC.com, June 25, 2005. http://www.msnbc.msn.com/id/8305249/ (accessed August 1, 2005).
"Survey: Parents Mellowing over Kids' Drugs." MSNBC.com, February 22, 2005. http://www.msnbc.msn.com/id/7010947/ (accessed July 29, 2005).
"Teens Targeted in Drugged Driving Campaign." MSNBC.com, December 3, 2004. http://www.msnbc.msn.com/id/6639590 (accessed July 29, 2005).
Hugh Downs Commentary on Marijuana. ABC News, broadcast November 1990.
See also: Nicotine
Marijuana (Encyclopedia of Drugs, Alcohol, and Addictive Behavior)
In the United States, this is the most common term for the HEMP plant Cannabis sativa and its mind-altering (PSYCHOACTIVE) products. The term derives from the Mexican Spanish mariguana/marihuana (sometimes explained as Mary's leaf or Mary's plant, or from María y Juan, that is, Mary and John, the source of the English slang Mary Jane or maryjane.) It came into recorded English about 1890 and has become the mainstream term in American publications, law, and general usage. The term cannabis is sometimes used in medical literature and by the British; it means hemp in Latin and is derived from the Greek, kannabis, itself borrowed into Greek from an unknown source. In ASIA, where the plant originated, it is grown legally and commercially both for its fiber content (it is used to make strong rope) and for its drug content; there it is called BHANG (from Sanskrit bhang) or bang, GANJA or churganja, and HASHISH.
Hemp grows easily throughout the tropics, sub-tropics, and temperate regions, varying from a few feet to 15 feet (4.6 m) in height. Once established, it reseeds itself and spreads to neighboring areas; when birds eat the seeds, the defecated seeds may be scattered over considerable distances and produce new plants.
Two genetic strains of hemp are recognized: one produces plants excellent for fiber with very little drug material; the other produces plants with weak fibers but much drug content (TETRAHYDROCANNABINOL, THC). To harvest the drug-laden plant, it is simply cut down and usually chopped into small pieces with all parts included. These clippings resemble lawn cuttings, so one of the slang terms is "grass." The major use of this form in the United States is for illegal marijuana cigarettes, often called reefers.
Since the early 1900s, marijuana has been considered the one drug that might introduce the susceptible to hard drugs, drug abuse, and drug dealing. In the United States until 1937, Cannabis had been used in medical practice for a number of conditions but marijuana use for its euphoric effect was relatively uncommon. By 1937, forty-six of the then forty-eight states had laws against the use of marijuana, and its use had already been made a criminal offense under federal law. Until the 1960s, it was smoked largely by African Americans and Hispanics in the United States but was generally shunned by the white majority. During the social and political protests of the 1960s, a change in attitudes allowed widespread but illegal marijuana use into all levels of society, along with an increase in the use of several other illegal drugs and a boom in the drug trade that continued into the 1990s.
Various historical allusions to medicinal plants suggest that Cannabis was known and used for several thousand years. The earliest references to the plant are in ancient Chinese and Indian writings. From India, the use of Cannabis spread to Persia, Assyria, and the rest of the Near East. The Arabs adopted and spread it through North Africa as they conquered those lands for Islam from the seventh to the fifteenth centuries. Islam forbids the use of ALCOHOL, but not explicitly Cannabis (since it was adopted after the laws established by the Prophet Muhammad, who lived from about 570 to about 632 A.D.). In Arabic, it is called HASHISH, meaning grass. After the Arabs crossed the Strait of Gibraltar into the Iberian peninsula in 711, they ruled there until 1492. Portugal and Spain did not generally adopt its use. The Spanish conquistadors, however, introduced Cannabis into the New World, where it was readily adopted by African slaves, who were already familiar with it because of Arab trade and the spread of Islam into their continent.
Like most plants, Cannabis contains many substances, perhaps two hundred or more. Those that relate most to the drug effects are a group of chemically similar compounds called cannabinoids. Of these, the most important and plentiful are cannabidiol (CBD), tetrahydrocannabinol (THC), and cannabinol (CBN). The biosynthetic pathway in the plant (that is, the step-by-step sequence in which the plant produces substances) goes from CBD to THC to CBN. Thus it is possible to identify the maturity of the plant by the relative content of these three cannabinoids. Immature plants show a preponderance of CBD; old plants may contain solely CBN; plants that are at their peak contain all cannabinoids, but mostly THC, which is the agent that produces the mind-altering effect. Some strains of plants contain variants on the THC structure, which usually have somewhat less drug effect than those with THC. Although some users contend that marijuana has different effects from those of isolated THC, most evidence indicates that virtually all of the mind-altering effects of marijuana are attributable to the THC content.
The THC content may vary greatly, depending on the genetic strain of the plant, the part of the plant involved (for example, the leaves or the flowers), and the maturity of the plant. The THC content of plants used for hemp production, such as those that grow wild in the U.S. Midwest, may be negligible to zero; marijuana produced from plants known for high drug content, such as sensemilla, may contain 2 to 3 percent THC. Manicured plants, from which the leaves are carefully separated and only the new leaves used for drug effect, may contain 3 to 4 percent THC. Hashish, which represents the ultimate in manicuring, generally contains 4 to 8 percent THC.
THC is sensitive to exposure to air and light. Thus, marijuana that is not protected from such exposure undergoes gradual degradation until the drug content is gone. When protected from air and light, marijuana may retain its activity for many months.
Marijuana may rank behind only CAFFEINE, alcohol, and NICOTINE as the most widely used drug in the world. It is estimated that between 200 and
In the United States, marijuana is a drug preferred by young people; the rate of marijuana use is therefore followed among schoolchildren to estimate changing trends. Survey responses of highschool students, concerning marijuana, show very wide variations. Overall, 3 to 17 percent (median 12%) reported at least a single use of marijuana during the preceding thirty days. Such use is relatively low compared with that of smoking at least one cigarette, 9 to 37 percent (median 31%), or having at least one drink of alcohol, 28 to 64 percent (median 54%). Thus, it would appear that marijuana is not nearly as widely used as two of our three national drugs. Although this data indicates a trend toward decreased use of and greater concern about marijuana compared with nicotine and alcohol, this pattern has not held long enough to establish a true trend; it may be simply a minor blip.
A number of factors seem to contribute to use of marijuana among young people. Being male, using cigarettes and alcohol, and becoming delinquent are predisposing factors. Coming from a broken home and performing poorly in school are also predictive factors. Among adolescents in Australia and New Zealand, use of stimulants, HALLUCINOGENS, NARCOTICS, and SEDATIVES was virtually limited to those young people who used marijuana. Overall, it appears that school factors are less predictive of Cannabis use than are other social factors.
Marijuana has a wide range of pharmacologic effects that suggest actions like those of stimulants such as the AMPHETAMINES, hallucinogens such as LSD, and depressants such as alcohol, SEDATIVES, atropine, or MORPHINE. Thus, marijuana does not fit any single traditional pharmacologic classification, and, hence, must be considered as a separate class.
The experienced smoker of marijuana is usually aware of a drug effect after two or three inhalations. As smoking continues, the effects increase, reaching a maximum about twenty minutes after the smoke has been finished. Most effects of the drug have usually vanished after three hours, by which time tests show that concentrations of THC in the body's plasma are low. Peak effects after eating marijuana may be delayed for three to four hours, but may then last for six to eight hours.
The early stage is one of being high, characterized by euphoria, uncontrollable laughter, alteration of one's sense of time, depersonalization, and sharpened vision. Later, the user becomes relaxed and experiences introspective and dreamlike states, if not actual sleep. Thinking or concentrating becomes difficult, although by force of will the person can concentrate to some extent.
Two characteristic signs of Cannabis intoxication are increased pulse rate and reddening of the conjunctiva (the whites of the eyes). The latter correlates well with the presence of detectable concentrations of THC in the plasma. Pupil size is not changed. The blood pressure may fall, especially in the upright position (orthostatic hypotension). An antiemetic (decrease in sense of nausea) effect may be present, and muscle weakness, tremors, unsteadiness, and increased deep-tendon reflexes (such as the knee jerk) may also be noted.
Virtually any performance test shows impairment if the doses are large enough and the test is difficult enough, although no distinctive biochemical changes have been found in human beings.
TOLERANCE to Cannabis has been demonstrated in virtually every animal species that has been tested. It is apparent in human beings only among heavy long-term users. Different degrees of tolerance develop for different effects of the drug, with tolerance for the tachycardiac effect (increased pulse rate) developing fairly rapidly. A mild WITHDRAWAL syndrome has been noted following very high doses.
The ambiguity surrounding the health hazards of Cannabis may be attributed to a number of factors besides those that ordinarily prevail. First, from animal studies, it has been difficult to prove or disprove health hazards in human beings. Second, Cannabis is still used mainly by young persons in the best of health. Third, Cannabis is often used in combination with tobacco and alcohol, among licit drugs, as well as with a variety of other illicit drugs. Finally, the whole issue of Cannabis use is so laden with emotion that serious investigations of the health hazards of the drug have been colored by the prejudices of the experimenter, either for or against the drug as a potential hazard or benefit to health.
Cannabis may directly produce an acute panic reaction, a toxic delirium, an acute paranoid state, or acute mania. Whether it can directly evoke depressive or schizophrenic states, or whether it can lead to sociopathy or even to the so-called AMOTIVATIONAL SYNDROME is much less certain.
That Cannabis use may make schizophrenia already present even worse is beyond any question. Such worsening followed acutely after use of Cannabis by schizophrenics, despite continued maintenance of antipsychotic drugs, and other adverse reactions were encountered among seventy patients in Swedennxiety reactions, flashbacks, dysphoric reactions, and abstinence syndromes.
Whether chronic use of Cannabis changes the basic personality of users so that they become less impelled to work and to strive for success has been a vexing question. As with other questions concerning Cannabis use, it is difficult to separate consequences from possible causes.
If marijuana were to become an accepted social drug, it would be important to know its effects on driving ability. Fully 50 percent of the fatal auto accidents in the United States are associated with alcohol, another social drug. Neither experimental nor epidemiological approaches to the marijuana question have yet provided definitive answers.
For persons with heart disease caused by hardening of the coronary arteries or by congestive heart failure, the effects of Cannabis smoking would be harmful: tachycardia, orthostatic hypotension, and increased concentrations of carbon monoxide in the blood.
Clearly, smoking of any kind is bad for patients with angina, but the greater effect of Cannabis as compared with tobacco in increasing heart rate makes this drug especially bad for such patients. Fortunately, thus far, few angina patients have been devotees of Cannabis.
Virtually all users of Cannabis in North America take the drug by smoking. As inhaling any foreign material into the lung may have adverse consequences, well proven in the case of tobacco, this mode of administration of Cannabis might also be suspect. A formal study has shown that very heavy marijuana smoking for six to eight weeks caused mild but significant airway obstruction.
The issue of damage to lungs from Cannabis is somewhat unclear because many Cannabis users also use tobacco. As yet, it is far easier to find pulmonary cripples from the abuse of tobacco than it is to find any evidence of clinically important weakness of the lungs caused by smoking Cannabis.
Endocrine and Metabolic Effects.
A review of literature on this subject concluded that sperm production was decreased, but without evidence of infertility. Ovulation was inhibited as luteinizing hormone, which stimulates ovulation, was decreased.
A number of test-tube studies, using both human and animal material, suggest that cell-mediated immunity (the capacity of white blood cells to fight invading bacteria, viruses, or cancer cells) may be decreased after exposure to Cannabis. Clinically, one might assume that sustained impairment of cell-mediated immunity might lead to increased opportunistic infections or to increased prevalence of cancer, as seen in the current epidemic of ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS). No such clinical evidence has been discovered.
For many centuries, Cannabis was used as a treatment, but only during the nineteenth century did a particularly lively interest develop for exploiting its healing powers. Cannabis was then reported to be effective in treating tetanus, convulsive disorders, neuralgia, migraine, menstrual problems, psychoses following childbirth, insomnia in the aged, depression, and gonorrhea, as well as in helping cure addiction to opium or to chloral hydrate. In addition, it was used to stimulate appetite and to relieve the pain and anxiety of patients terminally ill with cancer. Few of these claims have even been properly tested in clinical studies.
Antiemetic for Patients in Cancer Chemo-therapy.
An antiemetic is a substance that suppresses vomiting. CANCER chemotherapy, especially with the agent cisplatin, produces severe nausea and vomiting, which is extremely difficult to treat with ordinary antiemetic drugs, such as prochlorperazine. This complication is so severe that many patients forgo effective cancer chemotherapy. The antiemetic effects of Cannabis had been suggested as early as 1972. In that year, a synthetic drug similar to THC, nabilone, was developed. It has been tested extensively for antiemetic activity. A crossover study comparing nabilone with prochlorperazine revealed significantly better results (that is, less nausea and vomiting) following nabilone therapy, although side effects from nabilone were also common.
The potential role of THC as an antiemetic may have become irrelevant because of recent developments. Metoclopramide, a newly developed antiemetic unrelated to the cannabinoids, has been found to be effective when given in high intravenous doses. Lorazepam, dexamethasone, and ondansetron are also useful as antiemetic agents when given by injection. These drugs are often used in various combinations, which meet most requirements. Thus, THC may be superseded even before it has had widespread clinical trial.
The disease glaucoma causes pressure in the eyeball to increase greatly. If untreated, it can lead to blindness. Discovery of the ability of Cannabis to lower intraocular (inside the eyeball) pressure was more or less a matter of chance. This pressure was measured as part of a multifaceted study of the effects of chronic smoking of large amounts of Cannabis: it decreased as much as 45 percent in nine of eleven subjects, thirty minutes after smoking.
This exploitation of cannabinoids for treatment of glaucoma will require much further developmental work to ascertain which cannabinoid will be lastingly effective and well tolerated topically.
Cannabinoids have been found to have analgesic (pain-relieving) activity, and efforts are being made to synthesize new compounds that separate this action from the others. They have also been used for relaxing muscles, for treating bronchial asthma, and for stopping convulsions. Thus far, none of these additional potential therapeutic uses has been fully established.
TREATMENT OF MARIJUANA USE
In general, marijuana users, even those whose use is heavy, do not feel compelled to seek treatment unless such use is complicated by other drugs, such as COCAINE or alcohol. In this case, treatment efforts are usually directed toward the complicating drug. Thus, treatment programs directed specifically at marijuana use are rare. A TWELVE-S TEP approach, similar to that for alcohol, has been proposed, but its feasibility and its efficacy have not been tested.
Since about 1950 (but not much prior to that time) in the United States, smoking of marijuana has been linked statistically to the use of other illegal drugs, such as heroin and cocaine. Most observers have concluded that the link is sociological rather than biological, and that the use of marijuana is a marker for individuals who are more prone to seek new experiences even when these violate social norms and local laws. Further, the process of obtaining illegal marijuana increases the likelihood of contact with dealers and other individuals who have access to drugs such as HEROIN. Consequently, marijuana has been referred to as a "gateway" drug, one whose use often leads to the use of other illegal drugs. Some programs are aimed at preventing even experimentation with marijuanaot only for whatever inherent benefits this approach may have, but also in the hope that in doing so the movement to other more potentially lethal drugs will be prevented.
Despite its widespread use, marijuana has not yet been admitted to the company of accepted social drugs such as alcohol and nicotine. Laws remain that prescribe penalties for its possession, use, and sale. In some jurisdictions, possession and use of small amounts of the drug is a civil crime punishable only by a small fine. Despite the liberalization of the law in these areas, they have not been overrun with eager marijuana users. Perhaps the reason is that in most other jurisdictions, laws against its use are rarely enforced. Enforcement can be capricious, however, when employed in situations in which more serious crimes cannot be adequately documented.
A new drug application was approved for THC (Marinol) to be used therapeutically for control of the nausea and vomiting associated with cancer chemotherapy. Thus, THC was moved from Schedule 1 of controlled substances (no medical use) to Schedule 2 (medical use despite potential for abuse). Nabilone, the synthetic drug similar to THC, used for the same purpose, also has this status.
Thus far, no attempt has been made to establish legal limits on the amounts of THC in the blood that might be construed as impairing automobile driving. No doubt the issue has not yet appeared to be of enough gravity, since marijuana contributes little to the danger of driving as compared with alcohol.
(SEE ALSO: Adolescents and Drug Use; Cannabis Sativa; Complications; ; Driving, Alcohol, and Drugs; High School Senior Survey; Marihuana Commission; Yippies)
EBIN, D. (1961). The drug experience. New York: Orion Press.
HOLLISTER, L. E. (1989). Drugs of abuse. In B. G. KATZUNG (Ed.). Basic and clinical pharmacology, 4th ed. San Mateo, CA: Appleton & Lange.
PETERS, H., & G. N. (Eds.). (1973). Hashish and mental illness, by J. J. Moreau et al. (trans. from the French by G. J. Barnett). New York: Raven Press.
LEO E. HOLLISTER
REVISED BY JAMES T. MCDONOUGH, JR.