Developmental, gender, and comorbidity differences in clinically referred children with ADHD

Attention-deficit/hyperactivity disorder (ADHD) is the most prevalent child psychiatric disorder. and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) recognizes three subtypes: predominantly inattentive, predominantly hyperactive/impulsive, and combined (inattentive and hyperactive/impulsive). This study examined age, gender, and comorbidity differences in ADHD subtypes, using a screening checklist based on DSM-IV criteria. Parent- and teacher-completed checklists were obtained for clinic-referred children and adolescents between the ages of 3 and 18 years. Findings indicated that few youngsters exhibited symptoms of hyperactivity/impulsivity in the absence of inattention. Hyperactive/impulsive behavior was more common in the youngest age group (3-5 years), whereas inattention was more common in adolescents. Boys were overrepresented for each subtype of ADHD; however, the proportion of boys to girls did not differ for the various subtypes. Youngsters who exhibited symptoms of both hyperactivity/impulsivity and inattention were more likely to show oppositional and conduct disorder behaviors and anxiety than those who were only inattentive. The findings from this study suggest that even among children who meet criteria for one of the subtypes of ADHD, age and gender differences may be important variables in diagnosis.