A FAMILY STUDY OF OBSESSIVE-COMPULSIVE DISORDER

Objective: The goal of this study was to determine IJ whether obsessiv e-compulsive disorder is familial, 2) whether there is a familial rela tionship between obsessive-compulsive disorder and Gilles de la Touret te's syndrome and chronic tics, and 3) whether different familial type s of obsessive-compulsive disorder exist. Method: In this family study , all available first-degree relatives of 100 probands with obsessive- compulsive disorder were interviewed directly with structured intervie ws, and best-estimate diagnoses were assigned. In addition to the 466 first-degree relatives of the probands, 113 comparison subjects who we re first-degree relatives of 33 psychiatrically unaffected subjects we re studied with the same interviews. Results: The rates of obsessive-c ompulsive disorder and subthreshold obsessive-compulsive disorder were significantly greater among the relatives of the probands with obsess ive-compulsive disorder (10.3% and 7.9%, respectively) than among the comparison subjects (1.9% and 2.0%, respectively). Furthermore, the ra te of tics (Tourette's disorder and chronic tics) was also significant ly greater among the relatives of the probands (4.6%) than among the c omparison subjects (1.0%). The relatives of female probands with obses sive-compulsive disorder were move likely to have tics, and the relati ves of probands with early onset were at higher risk for both obsessiv e-compulsive disorder and tics. Conclusions: Obsessive-compulsive diso rder is a heterogeneous condition. Some cases are familial and related to tic disorders, some cases are familial and unrelated to tics, and in other cases there appears to be no family history of either obsessi ve-compulsive disorder or tics.