Attention deficit hyperactivity disorder: comorbidity and medication use.

Children evaluated for attention deficit hyperactivity disorder (ADHD) may have other disorders resembling ADHD leading to inappropriate stimulant medication use. This study was completed to identify relationships between referral complaints of ADHD, behavior problems or learning problems and age, gender, final diagnosis, and medication use. One hundred eighty-nine children ages 2 to 15 years referred for evaluation of ADHD, behavior or learning problems were evaluated by an interdisciplinary team. Diagnoses of ADHD, specific learning disability (SLD), mental retardation (MR), developmental language disorders (LANG), and other behavior disorders (DIS) were established. Medication use pre- and post-evaluation was reviewed. Forty-three percent of all subjects had a final diagnosis of ADHD. Forty percent referred specifically for presumed ADHD did not have it. More children older than 5 years were diagnosed as having ADHD than those 5 years old or younger (p < 0.0001). More subjects 5 years old or younger were diagnosed as having LANG than those older than 5 years (p < 0.0001). Fewer subjects with a chief complaint of ADHD were diagnosed with MR than those with behavior or learning problems (p = 0.001). In subjects 5 years old or younger, 35% were diagnosed with MR and 49% with other DIS. In children older than 5 years, 41% were diagnosed with SLD. Ten percent of subjects without ADHD were using stimulants. Only 48% of subjects with confirmed ADHD took stimulants. Children presenting with behavior problems or those 5 years old or younger are at higher risk for MR, LANG, and DIS and less likely to have ADHD. Children presenting with learning problems or those older than 5 years are more likely to have SLD or ADHD. Multiple diagnoses were common for all ages and presentations. Ten percent of children without confirmed ADHD used stimulants before evaluation.