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 (inattentiv e and hyperactive/impulsive). This study examined age, gender, and comorbid ity differences in ADHD subtypes, using a screening checklist based on DSM- IV criteria. Parent- and teacher-completed checklists were obtained for cli nic-referred children and adolescents between the ages of 3 and 18 years. F indings indicated that few youngsters exhibited symptoms of hyperactivity/i mpulsivity in the absence of inattention. Hyperactive/impulsive behavior wa s more common in the youngest age group (3-5 years), whereas inattention wa s more common in adolescents. Boys were overrepresented for each subtype of ADHD; however, the proportion of boys to girls did not differ for the vari ous subtypes. Youngsters who exhibited symptoms of both hyperactivity/impul sivity and inattention were more likely to show oppositional and conduct di sorder behaviors and anxiety than those who were only inattentive. The find ings 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 v ariables in diagnosis.