Sex differences in young children who meet criteria for attention deficit hyperactivity disorder

Examined sex differences in a mostly clinic-referred sample of 127 children (22 girls, 105 boys) who met Diagnostic and Statistical Manual of Mental Disorders (4th ed.; [DSM–IV], American Psychiatric Association, 1994) criteria for attention deficit hy-peractivity disorder (ADHD) and 125 comparison children (24 girls, 101 boys) matched on age, sex, and race-ethnicity. Children in both groups ranged in age from 3 years, 10 months to 7 years, 0 months. Both girls and boys who met criteria for ADHD were more impaired than same-sex controls on a variety of measures when intelli-gence and other types of psychopathology were controlled. Teachers reported that boys with ADHD were more inattentive and more hyperactive/impulsive than girls with ADHD. These findings suggest that the diagnosis of ADHD is valid for both girls and boys in this young age range. Young girls and boys who meet DSM–IV criteria for ADHD are more similar than different, but boys tend to display more symptoms of ADHD, particularly in school. The prevalence of attention deficit hyperactivity disorder (ADHD) has been found to be higher among boys and girls in many studies, although the male to fe-male ratio is apparently smaller in population-based samples than in clinic samples (Barkley, 1998; Gomez