Autonomic activity in children and adolescents with obsessive-compulsive disorder.

Electrodermal activity and heart rate were recorded from 55 children and adolescents with obsessive-compulsive disorder (OCD) and 58 normal subjects in a protocol that included rest and mild stress periods, and nonsignal and signal stimuli, to determine if autonomic activity might be involved in the pathogenesis of OCD or might be related to important clinical differences. Few differences were observed between OCD and normal subjects despite adequate power to detect small differences due to the large number of subjects. Thus, autonomic activity appears not to be an important etiological factor in childhood OCD. However, electrodermal activity showed consistent positive correlations with ratings of the severity of OCD symptoms (but not with anxiety or depression ratings), suggesting that severely afflicted cases are autonomically sensitive to OCD-related stimuli or, conversely, that low electrodermal activity may be protective of symptom severity. Patients with a coexisting tic disorder (not Tourette's syndrome) had larger electrodermal responses to a novel stimulus and higher heart rate variability than those without tics but did not differ from normal subjects. These few differences seem insufficient to support the hypothesis of a separate etiology of OCD cases with a coexisting tic disorder.