Chapter 28: Attention Deficit Hyperactivity Disorder

INTRODUCTION

Attention deficit hyperactivity disorder (ADHD) is a condition typically first evident in early childhood. Symptoms include difficulties with attention, concentration, and short-term memory as well as impulsivity. Children with ADHD are overly active (as if “driven by a motor”) and cannot control ongoing activity ranging from fidgeting to difficulty remaining seated for 5 minutes to inappropriately running, jumping, and yelling in public places. Since these deficits significantly impair academic performance and are disruptive in a typical classroom, concerns about ADHD usually arise during kindergarten or first grade. However, ADHD is a lifelong condition with functional impairment extending throughout adulthood.

Recent data from the Centers for Disease Control (CDC) suggest a prevalence of ADHD between 9% and 10% of children. There is debate about whether ADHD’s incidence is increasing historically. To date, the majority of epidemiologic studies have been conducted in North America and Europe. However, available data suggest that the condition has similar prevalence rates internationally. Even within the United States, there is also considerable variability in prevalence rates that may reflect differing diagnostic practices, differing definitions of the condition, or both. A recent U.S. study by the CDC reported state-based prevalence rates ranging from 5.6% (Nevada) to 15.6% (North Carolina). ADHD disproportionately affects males with a sex ratio between 3:1 and 9:1, with more conservative figures in clinical rather than community samples. Lower socioeconomic status (SES) has been associated with increased ADHD rates.

Diagnostic criteria for ADHD include two symptom clusters: inattention (failing to give attention to detail, problems maintaining attention, not appearing to listen when spoken to directly, failure to follow through on instructions for completion of schoolwork or other tasks, problems with organization, avoiding activities requiring sustained concentration, losing important items, being easily distracted, and forgetfulness), or hyperactivity/impulsivity (fidgeting, inability to remain seated, inappropriate running and climbing, difficulty playing quietly, acting as if “driven by a motor,” excessive talking, blurting out answers before questions are finished, difficulty taking turns, and intruding upon others’ activities and/or conversations). Children must have at least six symptoms from either (or both) the inattention group of criteria and the hyperactivity/impulsivity criteria, whereas older adolescents and adults (over the age of 17 years) must present with five criteria with some symptoms present before age 12.