Attention Deficit Disorder

A persistent and frequent pattern of developmentally inappropriate inattention and impulsivity, with or without hyperactivity.

This definition of attention deficit disorder (ADD), from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), shifts the focus from excessive physical activity. Although validation of ADD as a specific diagnosis has been difficult, no study has been able to establish the converse. ADD is implicated in learning disorders and can influence the behavior of children at any cognitive level, except for moderate to profound mental retardation. ADD estimatedly affects 5 to 10% of school-aged children, accounting for half of the childhood referrals to diagnostic clinics. ADD tends to occur in families and is common in first-degree biological relatives. ADD with hyperactivity and impulsivity is seen 10 times more frequently in boys than girls. Many now believe that ADD is a difference rather than a deficit or disorder in brain biochemistry resulting in a difference in approach to learning.

Etiology

Etiology is unknown. Several theories advocating biochemical, sensorimotor, physiologic, and behavioral correlates and manifestations have been proposed. Fewer than 5% of children with ADD have symptoms and signs of neurologic damage; CT scans, MRIs, and EEGs have not shown abnormalities in others. The leading hypothesis suggests neurotransmitter abnormalities in dopaminergic and noradrenergic systems with decreased activity or stimulation in upper brain stem and frontal-midbrain tracts. Toxins, neurologic immaturity, infections, drug exposure in utero, head injuries, and environmental factors have also been hypothesized.

Symptoms, Signs, and Diagnosis

The primary signs of ADD, with or without hyperactivity, are frequent and severe inattention and impulsivity. ADD with hyperactivity is diagnosed when the signs of overactivity and behavioral impulsivity are obvious and has recently been referred to as a deficiency in response inhibition. Inappropriate inattention, eg, poor sustained attention, causes increased rates of activity and impersistence or reluctance to participate or respond. Although children with ADD and without hyperactivity may not manifest high activity levels, most exhibit restlessness or jitteriness and impulsiveness, while some may be passive or lethargic. These features are qualitatively different from those seen in conduct and anxiety disorders.

DSM-IV criteria for ADD include nine signs of inattention, six signs of hyperactivity, and three signs of impulsivity. All signs do not have to be present. DSM-IV criteria also indicate that symptoms must be present in two or more situations (eg, home and school) and that symptoms impair social or academic functioning.

The signs of inattention are (1) often fails to pay close attention to details, (2) has difficulty sustaining attention in work and play, (3) does not seem to listen when spoken to directly, (4) often does not follow through on instructions and fails to finish tasks, (5) often has difficulty organizing tasks and activities, (6) often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort, (7) often loses things, (8) is easily distracted by extraneous stimuli, and (9) is often forgetful.

Signs of hyperactivity are (1) often fidgets with hands or feet or squirms, (2) often leaves seat in classroom and elsewhere, (3) often runs about or climbs excessively, (4) has difficulty playing or engaging in leisure activities quietly, (5) is often on the go or acts as if "driven by a motor," and (6) often talks excessively.

Signs of impulsivity are (1) often blurts out answers before questions have been completed, (2) often has difficulty awaiting his turn, and (3) often interrupts or intrudes on others.

DSM-IV recognizes three ADD subtypes: a combined attention deficit and hyperactivity type, a predominantly inattentive type, and a predominantly hyperactivity-impulsivity type. Inappropriate inattention must always be present for a diagnosis, thus the third subtype must be interpreted with caution.

Primary inattention tends to appear when the ADD child is involved in tasks that require continuous performance, vigilance and rapid reaction time, visual and perceptual search, systematic and sustained listening, and undivided attention. Inattention and impulsivity restrict development of academic skills, thinking and reasoning strategies, motivation for school, and adjustment to social demands.

Associated symptoms are frequently noted: motor incoordination or clumsiness, nonlocalized "soft" neurologic findings, perceptual-motor dysfunctions, EEG abnormalities, emotional lability, opposition, anxiety, aggressiveness, low frustration tolerance, poor social skills and peer relationships, sleep disturbances, bossiness, dysphoria, and mood swings.

Clinical Course

Onset of ADD occurs typically before age 4 yr and invariably before age 7 yr. The peak age for referral has been between 8 and 10 yr; however, children with primary ADD often are not diagnosed until or after adolescence.

Early indicators vary, but most school-aged children diagnosed as having ADD with or without hyperactivity or impulsivity exhibited differences in motor development, tended to have brief attention spans (eg, did not play with toys or did so briefly), and usually had abnormally high activity levels during their preschool years. Children with hyperactivity often were described as hyperexcitable and were difficult to manage as toddlers and preschoolers.

In school these signs persist. Difficulty with tasks such as copying and printing may become apparent. Careless errors are frequent. Social and emotional immaturity after age 7 yr is prevalent in all types of ADD. Some children with ADD also are less responsive to positive and negative reinforcement (ie, praise and punishment). Many have problems with time; some are clumsy. They often seem to lack intrinsic motivation and do not consider long-term consequences of their behavior.

In general, school-aged children with ADD are a more homogeneous group than those referred before age 6 yr. Many ADD signs expressed during the preschool years indicate communication disorders, anxiety, and conduct disorders. During later childhood, however, ADD signs usually are specific and qualitatively distinct; eg, such children often exhibit continuous movement of the lower extremities, motor impersistence such as the purposeless movement and fidgeting of hands, impulsive talking, and a seeming lack of awareness of their environment. Commonly, they are not aggressive or oppositional but often become noncompliant or defiant. Some studies have shown that about 30% have learning disabilities such as dyslexia; 40% exhibit depressed behavior by adolescence; 60% have problems such as aggressiveness, temper tantrums, anxiety, and low frustration tolerance with little provocation; and 90% have academic problems or are underachievers. Most are hands-on learners and have difficulty in passive-learning situations that require continuous performance and task completion.

Academic difficulties often do not begin until middle school years, and bright children with primary inattention can often compensate. ADD is task- and environment-related, and traditional classrooms and most academic activities exacerbate the problem. Substance abuse is often a secondary outcome if ADD is not identified and treated. Social and emotional immaturity are chronic. Poor peer acceptance and loneliness tend to increase with age and with the obvious display of symptoms. Children with primary inattention tend to have academic problems only.

Although hyperactivity tends to diminish with age, adolescents and adults may display residual symptoms of inattention and impulsivity, such as fidgetiness, restlessness, difficulty completing assigned tasks (eg, homework), and short attention span.

Diagnosis

Diagnosis often is difficult. No particular organic signs or set of neurologic indicators is specific, and no specific test has been validated. Although organic factors may have an etiologic role, the primary signs are behavioral, varying with situation and time. Rating scales and checklists, the predominant modes of identification, often cannot distinguish ADD from other behavioral disorders. Such data often are based on subjective observations made by untrained personnel. In a clinical setting, most behavior is not obvious, and unless the child is excessively overactive or impulsive, diagnosis is impossible without the use of specific tasks; eg, continuous performance tasks, vigilance and reaction-time tasks, tasks sampling paired-associate learning, and tasks increasing response uncertainty. Also needed are techniques that allow the observer to document objectively and qualitatively the type of overactivity, inattention, and impulsivity associated with ADD. Social and medical histories and school reports are essential for diagnosis.

Prognosis

Follow-up studies have shown that children with ADD do not outgrow their difficulties. Problems in adolescence and adulthood occur predominantly as academic failure, low self-esteem, and difficulty learning appropriate social behavior. Adolescents and adults with a history of ADD with impulsivity have a high incidence of personality trait disorders and antisocial behavior; most continue to display impulsivity, restlessness, and poor social skills. ADD persons with and without hyperactivity seem to adjust better to work than to academic and home situations. Interpersonal and social problems often persist into adulthood; depression and suicide attempts (not related to methylphenidate) are reportedly higher than in the normal population. Low intelligence, aggressiveness, social and interpersonal problems, and parental psychopathology are predictors of poor outcomes in adolescence and adulthood.

Treatment

Psychostimulant drugs combined with counseling best control symptoms. Used alone, psychostimulants have been effective predominantly with less impulsive ADD children and with children with primary inattention who have stable home environments. ADD children with poor impulse control often are less helped by treatment than are children with primary inattention.

Elimination diets, megavitamin treatments, use of antioxidants or other compounds, and nutritional and biochemical interventions (eg, the administration of neurochemicals) have had the least effect. The value of biofeedback is unsubstantiated. Most studies have found minimal change in behavior and no sustained benefit.

Psychostimulants: Psychostimulants have proved more effective than tricyclic antidepressants (eg, imipramine), caffeine, and other psychoactive drugs (eg, pemoline and deanol). Methylphenidate, a dopamine agonist, is the drug of choice and has fewer adverse effects than dextroamphetamine. Common adverse effects are sleep disturbances (eg, insomnia), depression or sadness, headache, stomachache, appetite suppression, elevated BP, and, with large continuous doses, chronic appetite suppression and growth reduction. Behavioral changes are related to dosage; learning often is enhanced at low doses (eg, methylphenidate 0.3 mg/kg/dose given before breakfast and lunch), and compliant behavior is most often improved at higher doses. However, cognition is often impaired at higher doses. Treatment often is started at low doses and is then increased to optimal levels (reflected by decrease in symptoms, improvement in task performance, and no side effects). Response to medication often is individual, and dosage is prescribed depending on the severity of the behavior and the child's ability to tolerate the drug. Methylphenidate is available in 5-, 10-, and 20-mg tablets and in a 20-mg sustained-release tablet. Many children have difficulty absorbing or tolerating methylphenidate sustained-release doses. Products with amphetamine mixtures purportedly have less influence on appetite and are sustained in the brain longer than standard doses of dextroamphetamine or methylphenidate; thus doses are lower.

Too much of a stimulant across the day can result in rebound reactions as the drug dissipates. Drugs often are prescribed to help the child only in school. Drug holidays are recommended; eg, the drug is not given on weekends, on school holidays, or during summer vacations. Placebo periods (for 5 to 10 school days to ensure reliability of observations) are recommended to challenge the need for drugs.

Long-term benefits of drugs alone have not been demonstrated conclusively. However, drugs have been shown to permit participation in activities previously inaccessible because of poor attention and impulsivity. Drugs often interrupt the cycle of inappropriate behavior, enhancing behavioral and academic interventions, motivation, and self-esteem.

Counseling: Counseling should include behavioral and cognitive therapies (eg, goal setting, self-monitoring, modeling, role-playing) and should help the child understand ADD. Structure and routines are essential.

Classroom behavior is often improved by cognitive-behavior modification, self-monitoring techniques, environmental control of noise and visual stimulation, appropriate task length, novelty, coaching, and teacher proximity.

When difficulties persist at home, parents should be encouraged to seek professional assistance and referred for parent training and behavior management techniques. Behavior management techniques and contingencies such as token economies and self-monitoring with reinforcement often are effective. Children with ADD with hyperactivity and poor impulse control are often helped at home when structure, consistent parenting techniques, and well-defined limits are established.

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