I. Description of the problem.
A. Attention-deficit/hyperactivity disorder (ADHD) is not a simple medical diagnosis. Rather, it is a behavioral syndrome, suspected when a cluster of suggestive behaviors are consistently observed by parents and other caregivers early in the child’s life. In young children, these behaviors cause significant dysfunction in most of the important aspects of the child’s experience: challenging relationships with parents and other caregivers, teachers and peers, as well as behavioral and discipline problems in multiple settings, including home, school, and childcare. In the adolescent and adult, ADHD may impair job performance, adult relationships, academic achievement, and be associated with increased legal difficulties, motor vehicle accidents, smoking, and substance abuse.
1. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) diagnostic criteria for ADHD are found in Table 25-1. The DSM-IV-TR differentiates three types of ADHD: predominantly inattentive, predominantly hyperactive-impulsive and combined type. Although meeting these criteria may not be necessary to make a diagnosis in all cases, these criteria represent an excellent list of the symptoms for the pediatric clinician to explore during the diagnostic process.
2. Aside from the “official” behaviors endorsed by the DSM-IV-TR, other issues commonly seen in children with ADHD may be even more important to their social, emotional, and academic well-being. These include the following:
Emotional lability or immaturity (other children call him “a baby”; when mood swings are extreme, especially with hyperirritable periods, a diagnosis of bipolar disorder may be considered)
Resistance to environmental reinforcement (much less responsive to positive or negative reinforcement, often rendering behavioral interventions less effective)
Little sense of physical safety (leading to increased accidents).
Aggressive behaviors (a major red flag with perhaps the most problematic longterm prognosis, often related to later aggressive behaviors and full-blown conduct disorder if not addressed).
An oppositional stance to the world (another major red flag, suggesting a suboptimal and negative response of the environment to the behavioral challenges, perhaps presaging a full-blown oppositional defiant disorder if not promptly addressed).
Poor social skills (“socially tone deaf”) and poor peer relations (heartbreakingly few friends).
Low self-esteem (perhaps the most common damaging long-term outcome of all).
B. Epidemiology.
1. Prevalence studies yield confusing results, depending on the criteria and means for ascertainment. Probably the best estimate is 5%-10% of American school children have ADHD.
ADHD has been found worldwide, whenever it has been studied, with rates ranging from 3%-18%.
Higher rates are seen in children from low socioeconomic status, but it is unclear whether this represents a true increase or is the result of an environment with fewer resources to ameliorate the challenging behaviors.
2. Male to female ratio had been classically estimated at about 4-6:1. However, recent studies suggest a lower ratio, perhaps as low as 2:1. This is because the diagnostic criteria are oriented to the male presentation (with many externalizing behaviors) and may miss many females (who tend to be diagnosed at a later date, if at all, presenting with subtle attentional challenges in school and difficulties in their social relations).
C. Comorbidity of other diagnoses and ADHD is quite high, although it is often ambiguous whether a second diagnosis has been caused by the ADHD or is cause of behaviors that look like ADHD or coexists as a discrete but interacting true second diagnosis
(Table 25-2). More than one of these additional syndromes can be (and often are) identified in the same child. Some estimate that comorbid diagnoses are the rule, not the exception, and can be found in 50%-75% of all children with ADHD.
Table 25-1. ADHD: DSM-IV-TR criteria
1.
Six or more of the following symptoms of inattention (or both) have persisted for at least 6 months to a degree that is maladaptive and inconsistent with developmental level:
Inattention
a.
Often fails to give close attention to details or makes careless mistakes in schoolwork, work, or other activities
b.
Often has difficulty sustaining attention in tasks or play activities
c.
Often does not seem to listen when spoken to directly
d.
Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (not due to oppositional behavior or failure to understand instructions)
e.
Often has difficulty organizing tasks and activities
f.
Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (such as homework)
g.
Often loses things necessary for tasks or activities (toys, school assignments, pencils, books, or tools)
h.
Is often easily distracted by extraneous stimuli
i.
Is often forgetful in daily activities
Hyperactivity-impulsivity
2.
Six or more of the following symptoms of hyperactivity-impulsivity have persisted for at least 6 months to a degree that is maladaptive and inconsistent with developmental level:
Hyperactivity
a.
Often fidgets with hands or feet or squirms in seat
b.
Often leaves seat in classroom or in other situations in which remaining seated is expected
c.
Often runs about or climbs excessively in situations in which it is inappropriate (in adolescents or adults, may be limited to subjective feelings of restlessness)
d.
Often has difficulty playing or engaging in leisure activities quietly
e.
Is often “on the go” or often acts as if “driven by a motor”
f.
Often talks excessively
Impulsivity
g.
Often blurts out answers before questions have been completed
h.
Often has difficulty awaiting turn
i.
Often interrupts or intrudes on others (such as butting into conversations or games)
A.
Some hyperactive, impulsive, or inattentive symptoms that caused impairment were present before the age of 7 years.
B.
Some impairment from the symptoms is present in two or more settings (such as in school or work and at home).
C.
There must be clear evidence of clinically significant impairment in social, academic, or occupational functioning.
D.
The symptoms do not occur exclusively during the course of a pervasive developmental disorder, schizophrenia, or another psychotic disorder and are not better accounted for by another mental disorder (such as a mood, anxiety, dissociative, or personality disorder).
American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders (4th ed) Text Revision, Washington, DC: American Psychiatric Association, 2000.
aFor individuals (especially adolescents and adults) who currently have symptoms that no longer meet full criteria, “in partial remission” should be specified.
D. Etiology. ADHD likely has no single invariant cause, but likely represents the final common pathway for a host of neurological and environmental risks.
1. Genetic factors. The concordance rate of ADHD in identical twins is strikingly high: 0.6-0.8. In addition, first- and second-degree relatives (parents, siblings, and grandparents) of children with ADHD have a much higher incidence of the disorder (20%-25%). Abnormal level of protein production by candidate dopamine-related genes (D4, D2, DAT) is being implicated in some. These and other genes are active subjects of intense research.
Table 25-2. Comorbid disorders
Comorbid disorders
% Range of prevalence from several studies
Specific developmental disorders (academic skills disorders, language and speech disorders, motor skills disorder)
20-60
Mild mental retardation
3-10
Oppositional defiant disorder
30-60
Conduct disorder
10-50
Anxiety disorders of childhood or adolescence (separation anxiety disorder, avoidant disorder, overanxious disorder)
10-30
Depressive disorder
5-35 (in adults)
Bipolar disorder
0-10 (15% of adults)
Tic disorders
5-30
Other neurologic disorders
<10
Posttraumatic stress disorder
Unknown
2. Medical risks. Intrauterine exposure to maternal smoking and alcohol use increase the risk of ADHD. Premature and low-birth weight infants also show a higher prevalence. Increased lead levels, carbon monoxide exposure, and various heavy metals (e.g., cadmium) have been implicated in some cases.
a. Differences in the brain. Animal studies and the effects of psychoactive medications have led to speculations of altered neurotransmitter profiles and brain function in persons with ADHD. Recent positron emission tomography and functional magnetic resonance imaging) studies suggest underactivity in parts of the cerebral cortex, especially the frontal lobes, perhaps leading to the challenges in executive function and self-regulation described in ADHD. Other areas, which have been implicated in studies as having altered function include the cerebellar vermis, cingulated gyrus, frontal-striatal connections, basal ganglia, and brain stem.
b. Environmental factors. Environmental issues, such as parental psychopathology and low socioeconomic status, likely play more of a role in exacerbating (or at least not ameliorating) the behaviors of ADHD, rather than as a causal agent. A family environment that includes poor monitoring of behavior and a punitive approach to discipline, for example, may magnify the symptoms of ADHD.
E. Theories of ADHD. The most popular current theory of ADHD, posited by Russell Barkley, is that ADHD represents a disorder of “executive function.” This implies dysfunction in the prefrontal lobes so that the child lacks the ability for behavioral inhibition or self-regulation of such executive functions as nonverbal working memory, speech internalization, affect, emotion, motivation, and arousal. Because of this relative inability to inhibit, the child lives pretty much only in the “now” and lacks the ability to modify or delay behavior in view of future consequences.
F. Prognosis.
1. Symptoms persist in the majority of young adults and adults, but change in nature (hyperactivity replaced by feelings of restlessness).
2. Higher incidence of problems is seen, such as antisocial behaviors (about 20%), substance abuse (15%), and other DSM diagnosis (about 35%).
However, a recent meta-analysis suggests that the incidence of substance abuse in teens is less with those who were treated with stimulant medication.
3. The majority do well, especially those who were not aggressive or oppositional, who have a high IQ, and come from high socioeconomic backgrounds.
II. Making the diagnosis. There is no sine qua non for the diagnosis of ADHD. Rather, the pediatric clinician must analyze and integrate the reports of characteristic behaviors by multiple observers, occurring in a variety of different settings, over an extended period of time. These behaviors are described as occurring with greater intensity and frequency than is typical for other children of the same development age and, most importantly, are causing significant problems in the child’s functioning and relationships in those settings.
A. History: key clinical questions.
1. “Tell me about the behaviors that concern you? What, exactly does he do? Give me a specific example.” It is important to obtain specific examples to see if the behaviors sound truly more severe than other children at the same developmental level, or if
the parent has a low tolerance for a “normal,” albeit temperamentally active and intense child.
2. “Who else is concerned about these behaviors?” Since children with true ADHD are problematic in most or all settings across time and space, if only the parent is concerned but other significant caregivers or teachers are not, one’s index of suspicious should be raised of an etiology other than ADHD.
3. “When did you first become concerned about these behaviors?” Often the symptoms have been present for a long time before coming to your attention. Conversely, the abrupt onset of behavioral problems may suggest a stressful trigger and etiology.
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Attention-Deficit/Hyperactivity Disorder
Attention-Deficit/Hyperactivity Disorder
Steven Parker
L. Kari Hironaka
