Recent developments in the pharmacotherapy of attention-deficit/hyperactivity disorder (ADHD).

Abstract

Attention-deficit/hyperactivity disorder (ADHD) is a developmental disorder typically first identified in childhood that has been demonstrated to persist into adulthood. Core symptoms of the disorder include inattention (e.g., difficulty sustaining attention and effort in the classroom), overactivity (e.g., fidgets, difficulty remaining seated during meals), impulsivity (e.g., blurts out answers), and frequent shifts from one activity to another (American Psychiatric Association [APA], 1994). For the purpose of making a diagnosis, at least six symptoms must be identified, and the severity of symptoms must render a child as functionally impaired (APA, 1994). Onset of symptoms must be prior to 7 years of age, and symptoms must persist for a minimum of 6 months. Initial symptoms of ADHD typically appear at preschool, but the diagnosis is frequently made in elementary school when there is increased demand for modulating behavior and following directions. Symptoms during the elementary years are often more apparent due to greater demands for sustaining attention, particularly at school. There has been compelling data to suggest that the core symptoms of ADHD persist into adolescence and well into adulthood, with up to one half of ADHD children reporting problems as adults (see Brown et al., 2001). The prevalence of the disorder is estimated to range from 4% to 12% in general primary care settings (American Academy of Pediatrics [AAP], 2000), whereas the estimate is even higher in referred populations. The gender ratio is estimated to range from four to nine boys for every girl. The etiology of the disorder has been posited to be both neurological (i.e., differences in brain morphology between children with ADHD relative to their normally developing peers; Zametkin et al., 1990) and genetic, with approximately 65% of children with ADHD having at least one relative with ADHD, compared with 15% of normally developing peers (Barkley, 2001; Biederman, Farone, Keenan, Knee, & Tsuang, 1990). ADHD is frequently comorbid with other disorders, including mood, anxiety, learning disabilities, and disruptive behavior disorders (Brown et al., 2001). Co-occurring psychiatric conditions are believed to range from 9% to nearly one third of the children identified with ADHD within the primary care setting. Among referred populations, the prevalence of comorbidity is estimated to be about 33%. Proper assessment in addition to a comprehensive diagnostic interview must include data from collateral sources (i.e., parents and teachers), often collected by incorporating teacher and parent rating scales. In particular, the Conners Rating Scales (Conners, 1997) and the SNAP Checklist (Atkins, Pelham, & Licht, 1989) have been noted to perform well in the identification of children with ADHD. Contrary to popular lore, there is no specific psychometric assessment instrument, laboratory test, or diagnostic procedure (e.g., electronencephalogram, magnetic resonance imaging) that has demonstrated validity in the identification of the disorder.