Despite long-standing clinical concerns, relatively little is known about the comorbidity between attention-deficit/hyperactivity disorder (ADHD) and tic disorders. Therefore, we examined tic disorders in an ongoing prospective follow-up study of male subjects with ADHD, a sample unselected for any comorbid disorder.
One hundred twenty-eight male children and adolescents with ADHD and 110 male controls were comprehensively evaluated at baseline and 4 years later. We characterized tic disorders along with a wide range of neuropsychiatric correlates, including other comorbid disorders and indices of psychosocial function in multiple domains (school, cognitive, social, and family).
Compared with controls, subjects with ADHD showed more tic disorders at baseline and more new onsets were reported at follow-up. Attention-deficit/hyperactivity disorder and tic disorders appeared to be independent in course: in contrast to low rates of ADHD remission, tic disorders mostly remitted. The age-adjusted rate of ADHD remission was 20% and that of tic remission, 65%. Tic disorders had little effect on the psychosocial functioning of subjects with ADHD.
These findings suggest that comorbidity with a tic disorder has a limited effect on ADHD outcome. However, because of the relatively small sample of subjects with tic disorders, our conclusions should be considered preliminary until confirmed in larger studies of medicated and unmedicated children with ADHD with and without tic disorders.