Attention-deficit/hyperactivity disorder (ADHD) is the most recent diagnostic label for children and adolescents who present with attention, impulse control, and overactivity problems. Children and adolescents with ADHD are commonly referred to family physicians, pediatricians, pediatric neurologists, and child psychiatrists and psychologists. The attention-deficit category has become increasingly popular among clinicians, and while the Diagnostic and Statistical Manual of Mental Disorders (DSM-1V-TR; American Psychiatric Association, 2000) suggests that only 3% to 7% of all school-age children and adolescents are affected by the disorder, at least 10% of behavior problems seen in general pediatric settings are due to ADHD, and up to 50% in some child and adolescent psychiatric samples. In clinical samples, ADHD is diagnosed in nine males for every female, however the rate of ADHD among girls is rapidly increasing (Robison, Skaer, Sclar,& Galin, 2002). ADHD girls who are clinic-referred are as impaired as their male counterparts in inattention, internalizing behavior, and peer aggression.
ADHD not only has a financial impact, but also is associated with family stress, school disruption, and risk for criminality and substance abuse. School-age youths with ADHD and co-occurring psychopathology have inferior academic performance and poorer social, emotional, and adaptive functioning than their peers (Wilens, Biederman, Brown, Tanguay, Monuteaux, Blake, & Spencer, 2002).
ADHD's etiology is unknown, although multiple pathways have been suggested for this syndrome. Among those are heritability, which is high for ADHD. According to DSM-IV-TR, ADHD is more common in the primary biological relatives of children and adolescents with ADHD than in the general population. Neurophysiological theories have also been investigated. Porges (1984, 1998), for example, examined the physiologic correlates of attention. The inability to attend appropriately has been associated with a variety of diagnoses, including hyperactivity and learning disorders. Porges (1998) has suggested that these behavioral pathologies have a common physiological substrate. The inability of the hyperactive or learning-disabled child/adolescent to mediate and inhibit spontaneous activity is thought to be paralleled by a deficient inhibitory system manifested in the parasympathetic control of the heart. That is, individuals who exhibit an attention disorder may demonstrate relatively lower vagal tone, indicated by heart rate variability during periods when sustained attention is required.
Children with ADHD may vary considerably in their symptoms across situations. However, they are often described as having chronic difficulties in regard to inattention, impulsivity, and overactivity--the "holy trinity" of ADHD. Barkley (1990) notes that ADHD children/ adolescents commonly display these characteristics early, to a degree that is inappropriate for their age, and across a variety of situations. According to DSM-IV-TR criteria, symptoms must be "maladaptive and inconsistent with developmental level." The symptoms must also be present across two or more settings.
Early-onset ADHD frequently co-occurs with other disorders, and symptom overlap raises diagnostic problems. Common mimics of attention disorders are anxiety disorders and mood disorders, and these must be carefully ruled out.
ADHD is often comorbid with other disorders such as learning disabilities (LD), internalizing disorders, and externalizing disorders. Children with both LD and ADHD have more sociobehavioral problems than those with LD alone, and the former group comprises between 25% and 31% of students in LD classrooms (Forness, Kavale, & San Miguel-Bauman, 1998). About one-fourth of children/adolescents who are anxiety disordered have a comorbid diagnosis of ADHD (Perrin & Last, 1995).
Between 10% and 20% of children with ADHD have mood disorders, 20% have conduct disorders (CD), and up to 40% may have oppositional defiant disorder (ODD) (Goldman, Gonel, Bezman, & Slanetz, 1998). …