What are childhood disorders?
The concept of mental disorder, like many other concepts in science and medicine, lacks a consistent operational definition that covers all situations. A useful tool to evaluate mental disorders is the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM). The DSM is coordinated with the International Statistical Classification of Diseases and Related Health Problems (ICD), developed by the World Health Organization for all diseases. A comprehensive manual, the DSM conceptualizes a mental disorder as a syndrome characterized by clinically significant disturbance in an individual's cognition, emotional regulation, or behavior that reflects a dysfunction in the psychological, biological, or developmental processes underlying mental functioning. These disturbances must be more than expected and culturally sanctioned responses to a particular event, for example, the death of a loved one.
Mental disorders that are predominantly diagnosed during childhood or adolescence include intellectual disability, learning disorders, motor skills disorders, pervasive developmental disorders, attention-deficit disorders, feeding and eating disorders, tic disorders, and elimination disorders, among others. Other disorders are associated with adults, but children may have them as well. This second group includes neurocognitive disorders; mood disorders; anxiety disorders; somatic symptom disorders; factitious disorders; dissociative disorders; sleep-wake disorders; disruptive, impulse-control, and conduct disorders; and adjustment disorders. In the fifth edition of the DSM (DSM-5), each diagnostic chapter is organized by chronological order, with diagnoses most applicable to infancy and childhood listed first, followed by diagnoses more common to adolescence and early adulthood, and ending with diagnoses most relevant to adulthood.
Intellectual disability (also know as intellectual developmental disorder and formerly known as mental retardation) involves impairments of general mental abilities that affect adaptive functioning in three main areas: the conceptual domain, which includes skills in language, mathematics, reasoning, and memory; the social domain, which relates to empathy, interpersonal communication skills, and social judgment; and the practical domain, which involves self-management in areas such as personal care, job responsibilities, money management, and organization. On an intelligence quotient (IQ) test, intellectual disability is defined as two standard deviations or more below the mean, corresponding to an IQ score of 70 or below. A common misconception regarding intelligence tests is the assumption that these tests represent an absolute trait. A low score on an intelligence test might reflect below-average intellectual functioning, but it might also reflect illness, distraction, or a native language or sociocultural background that differs from that of the examiner or test creators, among other reasons. For this reason, the DSM-5 emphasizes both clinical assessment of impairments in adaptive functioning and standardized testing of intelligence when diagnosing intellectual disability.
There are four degrees of intellectual disability: mild, moderate, severe, or profound. The severity of intellectual disability is determined by impairments in adaptive functioning rather than by IQ score. Mild intellectual disability characterizes more than 80 percent of individuals with intellectual disabilities. By late adolescence, most individuals with mild intellectual disability can function up to about a sixth-grade academic level. As adults, these individuals typically live self-sufficiently in the community, although they may need assistance when they are in unusual, complex, or stressful situations. People with moderate intellectual disabilities have sufficient communication skills but may struggle with social cues. These individuals profit from vocational training and, with some support and instruction, can attend to personal care on their own. Severe intellectual disability is characterized by limited communication skills and the need for assistance in most activities of daily living. Most individuals with several intellectual disabilities benefit from residence in supportive housing. Individuals with profound intellectual disability typically require twenty-four-hour care, have very limited communications skills, and often have co-occurring sensory or physical disabilities. Individuals in this range account for only 1 to 2 percent of persons with intellectual disabilities.
There are many causes of intellectual disabilities, but psychiatrists identify a specific cause in only about 25 percent of cases. Causes for intellectual disability include genetics, metabolic conditions such as phenylketonuria (PKU) and congenital hypothyroidism, early problems in embryonic or perinatal development, environmental influences such as nutritional deficiencies in infancy or exposure to toxins in utero, and trauma.
In specific learning disorders, a child’s academic achievement is substantially below that expected for age, schooling, and level of intelligence. In children with learning disorders, the specific learning difficulty persists for at least six months despite intervention and instruction targeting the area of difficulty. Approximately 5 to 15 percent of school-aged children worldwide have a learning disorder. Learning disorders are different from normal variations in academic achievement and from learning deficits caused by lack of opportunity, poor teaching, or cultural factors. Impaired vision or hearing may affect learning ability, so vision and hearing should be assessed by a health care provider if a learning disorder is suspected. In order for an individual to fit the diagnostic criteria for a specific learning disorders, the learning difficulties must occur in the absence of intellectual disability, visual or hearing impairments, mental disorders such as anxiety or depression, neurological disorder, psychosocial difficulties, language differences, and lack of access to quality instruction.
Learning disorders can involve problems with reading, mathematics, written expression, or some combination of these areas. In reading disorder, a family pattern is often present. In mathematics and written expression disorder, parents or teachers typically notice a problem as early as the second or third grade but not earlier, because few children are exposed to mathematics or formal writing instruction before then.
Motor disorders include developmental coordination disorder, stereotypic movement disorder, Tourette syndrome, persistent (chronic) motor or vocal tic disorder, provisional tic disorder, other specified tic disorder, and unspecified tic disorder. Motor disorders are typically diagnosed in childhood. Motor disorders involve abnormal and involuntary movements and are often characterized by marked delays in motor development.
A tic is a sudden, rapid, recurrent, nonrhythmic, stereotyped motor movement or vocalization. For example, the person may have an eye tic that involves small, jerky, involuntary movement of the muscles surrounding the eye. All children and adults experience mild tics, but a tic disorder means that the tics are frequent, recurrent, and not due to substances or medical conditions.
Communication disorders include problems with expressive or receptive language, phonology, stuttering, or some combination of these areas. Aspects of these problems vary depending on their severity and the child’s age.
When the problem involves expressive language, the features may include limited speech, limited vocabulary, difficulty acquiring new words, and simplified sentences. Nonlinguistic functioning and comprehension, however, are within normal limits. When the problem involves difficulties with both expressive language and receptive language, the child also has difficulty understanding words, sentences, or specific types of words. When the problem involves phonology, the child fails to use developmentally expected speech sounds. Severity ranges from a limited vocabulary to completely unintelligible speech. Lisping may also be present. When the problem involves stuttering, the child has a disturbance in the normal fluency and time patterning of speech.
Autism spectrum disorder (ASD) is characterized by impaired social interactions or communication skills and by restricted or repetitive behaviors, interests, and activities. As of the DSM-5, ASD encompasses four diagnoses that were previously categorized as separate disorders in the fourth edition of the DSM: autistic disorder (autism), Asperger syndrome, Rett syndrome, and childhood disintegrative disorder. ASD is usually evident in the first years of life and may be associated with some degree of intellectual disability. ASD is sometimes observed with a diverse group of other general medical conditions, including chromosomal abnormalities, congenital infections, and structural central nervous system abnormalities.
ASD involves abnormal social interactions and communication and a restricted repertoire of activity and interests. The child may fail to maintain eye-to-eye contact or to share enjoyment, interests, or achievements spontaneously with others and may develop no age-appropriate peer relationships. The child also shows qualitative impairment in communication, such as delay in developing spoken language, inability to initiate or sustain a conversation, or repetitive use of language. Children with this disorder may be uninterested in other children, including siblings. In recent decades, major headway has been made in treating children with ASD through behavioral management therapy and cognitive behavioral therapy, particularly those children with ASD who benefit from early intervention.
Attention-deficit hyperactivity disorder (ADHD) involves persistent inattention or hyperactivity and impulsivity that is more severe than is typical for the child’s age. Several inattentive or hyperactive-impulsive symptoms must be present before the age of twelve, persist for at least six months, and be present in at least two settings, such as school and home. Most children with ADHD show a combined set of problems, including both inattention and hyperactivity. Symptoms of ADHD include failure to pay close attention to details, difficulty organizing tasks and activities, excessive talking, fidgeting, an inability to remain seated in appropriate situations, and frequent interruptions or intrusions.
These disorders include persistent feeding and eating disturbances. They include pica, rumination, feeding disorder, anorexia, and bulimia.
Pica involves persistently eating one or more nonnutritive substances, such as paint or dirt. The behavior is developmentally inappropriate and not part of a culturally sanctioned practice.
Rumination involves repeated regurgitation and rechewing of food after feeding. Infants may develop rumination after a period of normal functioning, and it lasts for at least one month. The infant shows no apparent nausea, retching, disgust, or associated gastrointestinal disorder. Age of onset is between three months and twelve months.
Feeding disorder involves persistent failure to eat adequately without a gastrointestinal or other general medical explanation. Infants with this disorder may be more irritable and difficult to console during feeding than other infants. Age of onset is before six years.
Anorexia nervosa, often called simply anorexia, involves refusing to maintain a minimally normal body weight (85 percent less than expected), being intensely afraid of gaining weight, and having a distorted body image. Teenaged girls with anorexia may have such a low body weight that they stop having menstrual periods.
Bulimia nervosa, often called simply bulimia, involves binge eating and inappropriate compensatory methods to prevent weight gain, such as purging or using laxatives excessively. Episodes of binging and purging occur at least twice a week for at least three months. Individuals with this disorder experience a lack of control over eating, and their self-evaluation is unduly influenced by body shape and weight. Bulimia is also most typical of adolescent girls from industrialized societies.
Elimination disorders involve age-inappropriate soiling (encopresis) or wetting (enuresis). Most often the behavior is involuntary, but occasionally it may be intentional. The incontinence must not be due to substances or a general medical condition.
Encopresis involves passage of feces into inappropriate places such as clothing or the floor that occurs at least once a month for at least three months. The child must be at least four years old. Most commonly, there is evidence of constipation and feces are poorly formed. Less often, there is no evidence of constipation and feces are normal. Encopresis is more common with boys than with girls.
Enuresis involves repeated voiding of urine into bed sheets or clothes that occurs at least twice per week for at least three months or else causes clinically significant distress or impairment. The child must be at least five years old. Nocturnal enuresis occurs only at night and is most common. Diurnal enuresis occurs only during the day and more often with girls than with boys. It is uncommon after age nine.
A few other disorders are more characteristic of children than adults. They include separation anxiety disorder, selective mutism, reactive attachment disorder, and stereotypic movement disorder.
Although most children experience some transient anxiety when separated from a loved one, children with separation anxiety disorder have excessive anxiety when separated from the home or from their attachment figures. The anxiety lasts for at least four weeks, begins before age eighteen years, and causes clinically significant distress or impairment.
Children with selective mutism persistently fail to speak in specific social situations (such as school or with playmates) where speaking is expected, despite speaking in other situations. The disturbance interferes with educational or occupational achievement or with social communication and bonding. Selective mutism lasts for at least one month and is not limited to the first month of school, when many children may be shy and reluctant to speak.
Reactive attachment disorder involves markedly disturbed and developmentally inappropriate social relatedness in most contexts. It begins before age five and is associated with grossly pathological care, such as child abuse or neglect. In inhibited attachment, the child persistently fails to initiate and respond to most social interactions in a developmentally appropriate way. In disinhibited attachment, the child shows indiscriminate sociability or a lack of selectivity in the choice of attachment figures. Thus, the child has diffuse attachments and shows excessive familiarity with relative strangers.
Stereotypic movement disorder involves motor behavior that is repetitive, seemingly driven, and nonfunctional. For example, the child may repeatedly strike a wall. The motor behavior markedly interferes with normal activities or results in self-inflicted bodily injury that would require medical treatment if unprotected.
In addition to disorders associated with infancy, childhood, or adolescence, children may have behavioral or psychological disorders that are typically associated with adults. They include schizophrenia, mood disorders, anxiety, somatic symptom disorders, factitious disorders, dissociative disorders, sleep disorders, impulse-control disorders, and adjustment disorders.
Schizophrenia involves delusions, hallucinations, or disorganized speech and behavior, with symptoms lasting for at least six months. Onset is typically late teens to mid-thirties.
Depression involves loss of interest or pleasure in nearly all activities. Additional symptoms include changes in appetite, sleep, or activity; decreased energy; feelings of worthlessness or guilt; difficulty thinking, concentrating, or making decisions; and recurrent thoughts of death or suicide. Bipolar disorder involves at least one episode of mania as well as at least one episode of depression.
Anxiety disorders include panic disorder, agoraphobia, specific phobias, social anxiety disorder, and generalized anxiety disorder. Trauma- and stressor-related disorders include posttraumatic stress disorder and adjustment disorder. Obsessive-compulsive and related disorders include obsessive-compulsive disorder, body dysmorphic disorder, trichotillomania, and hoarding disorder.
Somatic symptom disorder is characterized by one or more chronic symptoms about which the patient is excessively concerned, preoccupied, or fearful, causing significant distress or dysfunction. Illness anxiety disorder is characterized by heightened bodily sensations and intense anxiety about the possibility of having an undiagnosed illness; patients with illness anxiety disorder may spend excessive amounts of time worrying about and researching health concerns, and they are not easily reassured about their health status.
Factitious disorders are characterized by intentionally produced physical or psychological symptoms. The motivation is to assume the sick role.
Dissociative disorders involve disruptions in consciousness, memory, identity, or perception that are more than ordinary forgetfulness. One dissociative disorder is psychogenic amnesia, which involves an inability to recall important personal information, usually of a traumatic or stressful nature. Another is dissociative identity disorder, formerly called multiple personality disorder, which is characterized by two or more distinct identities.
Sleep-wake disorders may be due to other mental disorders, medical conditions, or substances. Sleep-wake disorders arise from abnormalities in the ability to generate or maintain sleep-wake cycles. Symptoms of sleep disorder may include insomnia (difficulty initiating or maintaining sleep), hypersomnia (excessive sleepiness), narcolepsy (irresistible attacks of sleep), nightmares, sleep terror, or sleepwalking.
Disruptive, impulse-control, and conduct disorders are characterized by problems in emotional and behavioral self-control. The essential feature of impulse control disorders is a failure to resist an impulse, drive, or temptation to perform an act that is harmful to self or others.
Adjustment disorders involve a psychological response to an identifiable stressor that results in emotional or behavioral symptoms. As with other disorders, one must consider cultural setting in evaluating for the possibility of this disorder.
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