Evaluating the contributions of ADHD, OCD, and tic symptoms in predicting functional competence in children with tic disorders

Children with chronic tic disorders (CTD), including Tourette's Disorder (TD), demonstrate a higher incidence of comorbid conditions, including attention-deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). The relative contributions of tics versus ADHD and OCD symptoms for predicting impaired functioning in children with TD is unknown and existing studies on the topic are inconsistent. This study evaluated the unique contributions of tic severity, ADHD diagnostic status, and OCD symptom severity in predicting competence scores on the Child Behavior Checklist (CBCL) in a sample of children with CTD. Results of a hierarchical regression analysis show that both ADHD and OCD symptoms predicted decreased CBCL competence scores. When tic complexity was added, however, only ADHD and tic complexity continued to predict CBCL competence scores. These findings begin to resolve inconsistencies in existing literature and have important implications for understanding and treating children with CTD.