Observed classroom behavior of children with ADHD: relationship to gender and comorbidity.

Examined hypothesized gender and comorbidity differences in the observed classroom behavior of children with attention deficit hyperactivity disorder (ADHD). The behavior of 403 boys and 99 girls with ADHD, ages 7-10, was compared (a) to observed, sex-specific classroom behavior norms, (b) by sex, and (c) by comorbid subgroups. Boys and girls with ADHD deviated significantly from classroom norms on 15/16 and 13/16 categories, respectively. Compared to comparison girls, girls with ADHD had relatively high rates of verbal aggression to children. Boys with ADHD engaged in more rule-breaking and externalizing behaviors than did girls with ADHD, but the sexes did not differ on more "neutral," unobtrusive behaviors. The sex differences are consistent with notions of why girls with ADHD are identified and referred later than boys. Contrary to hypothesis, the presence of comorbid anxiety disorder (ANX) was not associated with behavioral suppression; yet, as hypothesized, children with a comorbid disruptive behavior disorder (DBD) had higher rates of rule-breaking, and impulsive and aggressive behavior, than did children with ADHD alone and those with ADHD+ANX. Elevated rates of ADHD behaviors were also observed in children with comorbid DBD, indicating that these behaviors are truly present and suggesting that reports of higher ADHD ratings in this subgroup are not simply a consequence of negative halo effects and rater biases.