What is methamphetamine?

Quick Answer
Methamphetamine is a psychostimulant in the phenoethylamine and amphetamine class of drugs. It is a white, odorless, bitter-tasting crystalline powder that is highly addictive. It is used medically to treat attention deficit hyperactivity disorder, exogenous obesity, and narcolepsy.
Expert Answers
enotes eNotes educator| Certified Educator
History of Use

A Japanese scientist first synthesized methamphetamine in 1919. Along with amphetamines, methamphetamine was given to both Axis and Allied soldiers during World War II as performance aids and to counteract sleep deprivation. Illegal use of methamphetamine rose in the United States in the 1960s, originating in the Southwest. Methamphetamine was supplied by labs in Mexico and smuggled into the United States through US border states. By the 1980s, methamphetamine had become increasingly popular in the Midwest and in the southern states, partially because of the availability of fertilizer that could be used as an ingredient in methamphetamine production.

Although the National Institute on Drug Abuse reports that methamphetamine use among teenagers is in decline, studies show that there are between 15 and 16 million methamphetamine abusers worldwide, a number some experts say is second only to marijuana use. Admission rates to rehabilitation centers for methamphetamine addiction are higher in some states than for cocaine or even alcohol abuse.

One of the methods of coping with the rising methamphetamine problem has been a slow but progressive change in treating addicts. Prison officials, psychologists, and legislators have made changes in the prison system so that prisoners addicted to methamphetamine can safely go through detoxification and receive further treatment.

Treatment for methamphetamine addiction has become specialized. The matrix model includes cognitive-behavioral therapy, family education, positive reinforcement for behavior change and treatment compliance, and a twelve-step program. No ideal medication has been found for treatment, although some studies have examined the use of the tricyclic antidepressant imiprazine (Tofranil).

Effects and Potential Risks

The physical effects of a methamphetamine high resemble those of the body in a fight-or-flight, hyperarousal response. Heart rate and blood pressure increases, and awareness is heightened with increased self-confidence.

Chronic methamphetamine use and methamphetamine overdose lead to extremely dangerous physical conditions, including myocardial infarction, cardiopulmonary arrest, seizures, hypoxic brain damage, hyperthermia, and intracranial bleeds. Psychiatric symptoms are extremely common and include insomnia, mood disorders, violent behavior, paranoia, and hallucinations.

Methamphetamine increases the release of and blocks the body’s reuptake of dopamine, which increases the levels of dopamine in the brain. The inability of the brain to release the excess dopamine creates the user’s rush or high. Chronic methamphetamine use leads to a change in the activity of the dopamine system, specifically a decrease in motor skills and impaired verbal learning skills. Chronic use also affects emotions, memory, and general cognitive abilities. Because methamphetamine is highly lipophilic, it enables a rapid and extensive transport across the blood-brain barrier. It is highly neurotoxic and can stay in the body’s system for eight to thirteen hours.

Even after a methamphetamine user stops using the drug, the damage to his or her brain continues. There is evidence of impairment of the anterior cingulated cortex, the area of the brain that influences cognitive functions and emotions and regulates behavior. The drug disables the ability to choose between healthy and unhealthy behaviors. Enhanced cortical gray matter volume also declines with age, leading to an accelerated rate of mental functioning, primarily because of a reduction in the number of neurons rather than shrinkage of gray matter. Methamphetamine users are at a greater risk for degenerative or cognitive diseases, and persons who are comorbid with depression are at a higher risk for dementia.

Methamphetamine use also increases the risk of transmission of the human immunodeficiency virus (HIV) and the hepatitis virus. Shared-needle use and higher risk sexual behavior increase the chances that a user will be infected with a sexually transmitted disease. Methamphetamine users who are HIV positive tend to suffer more neuronal injury and cognitive impairment.

A common physical trait of a chronic methamphetamine user is poor oral hygiene, or meth mouth. Methamphetamine use can cause a decrease in saliva output, leading to chronic dry mouth. Users will often drink large amounts of sugary carbonated soft drinks, which leads to severe dental decay. Many methamphetamine users also may grind or clench their teeth, causing tooth fractures.


Nakama, Helena, et al. “Methamphetamine Users Show Greater Than Normal Age-Related Cortical Gray Matter Loss.” Addiction 106.8 (2011): 1474–83. Print. A cross-sectional study that suggests that methamphetamine users suffer a decline in cognitive health at earlier ages than those who do not use methamphetamine.

Padilla, Ricardo, and Andre V. Ritter. “Meth Mouth: Methamphetamine and Oral Health.” Journal of Esthetic and Restorative Dentistry 20.2 (2008): 148–49. Print. Examines the occurrence of meth mouth.

Schep, Leo, Robin J. Slaughter, and D. Michael G. Beasley. “The Clinical Toxicology of Methamfetamine.” Clinical Toxicology 48 (2010): 675–84. Print. An overview of the biochemical mechanisms of methamphetamine on the brain and an extensive list of toxicokinetics and clinical features of methamphetamine abuse.

Websites of Interest

Drug Information Portal. National Library of Medicine


National Institute on Drug Abuse