Objectives: To determine whether juvenile obsessive-compulsive disorder (OCD) is familial and whether the rate of Tourette syndrome (TS) and tic disorders is higher among relatives of patients with OCD than among relatives of controls subjects.
Method: We assessed first-degree relatives of 35 juvenile OCD probands (aged 16 years or less) and 34 matched, psychiatrically unaffected control subjects, using the Diagnostic Interview for Children and Adolescents-Revised (DICA-R) (unpublished), a Questionnaire for tic disorders, the Children's Version of Leyton's Obsessional Inventory (CV-LOI), and the Children's Version of the Yale-Brown Obsessive Compulsive Scale (CY-BOCS). Similarly, we assessed adult relatives, using the Schedule for Clinical Assessment in Neuropsychiatry (SCAN), Leyton's Obsessional Inventory (LOI), the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), and a Questionnaire for tic disorders. The diagnoses were determined by consensus, using DSM-III-R criteria. We calculated age-corrected morbid risk, using Weinberg's method.
Results: The morbid risk for OCD among the relatives of OCD probands was 4.96%, while none of the relatives of unaffected control subjects had OCD. We did not diagnose TS in any of the relatives of either OCD probands or control subjects. We diagnosed chronic motor tic disorders in only 1 of the relatives of OCD probands, while none of the relatives of control subjects had any tic disorder.
Conclusion: Most juvenile cases of OCD are nonfamilial and unrelated to tic disorders, while only a few are familial. There is a need to re-examine the issue of familiality in cases of OCD, as well as its relation to TS, using larger community samples to better understand the hypotheses of familial transmission and comorbidity with tic disorders.