Comparison of internalizing and externalizing symptoms in children with attention-deficit hyperactivity disorder with and without comorbid tic disorder

This study examined the relation between internalizing and externalizing sy mptoms in two groups of prepubertal boys (with and without multiple chronic tic disorder) with diagnosed attention-deficit hyperactivity disorder (ADH D). Parents and teachers completed the Child Behavior Checklist (CBCL) and Teacher's Report Form (TRF), respectively. Children were carefully evaluate d for the absence of a chronic tic disorder. Boys with ADHD and chronic mul tiple tic disorder (ADHD/+tics) received significantly higher (p = .0032, B onferroni correction) scores for the Anxious/Depressed, Thought Problems, a nd Attention Problem scales of the CBCL and the Delinquent Behavior, Though t Problems, and Somatic Complaints scales of the TRF than did boys without chronic tic disorder (ADHD/-tics). Although many of the individual items th at differentiated (p < .05) the two groups of boys pertained to behaviors t hat characterize motor ties, obsessions, or compulsions, the ADHD/+tics gro up exhibited higher rates of anxious behavior (CBCL) and obscene language ( TRF) than did the ADHD/-tics group. Anxiety/depressive symptoms were associ ated with aggressive/oppositional behavior in both samples. Children with m ild tic disorder were more similar (CBCL) to ADHD/- ties boys than they wer e to children with more severe tic disorder. The relatively higher rate of comorbidity in the ADHD/+tics group suggests that ties may be a marker for more severe symptomatology in clinic-referred samples of children with ADHD . Furthermore, these data suggest that it is not the presence, per se, but rather the severity of tic disorder that is associated with higher rates of emotional and behavioral disturbances.