An exploratory study on obsessive-compulsive disorder with and without a familial component: Are there any phenomenological differences?

Familial studies on obsessive-compulsive disorders (OCD) have suggested that OCD is a heterogeneous condition, with some cases being familial and others being isolated cases in their families. Nevertheless, no studies evaluated whether there are clinical differences between OCD cases with and without a familial component, The current report presents data on the prevalence of OCD in first-degree relatives of OCD probands and compares phenomenological characteristics of familial and nonfamilial OCD types. The family study and the family history methods were used to estimate the prevalence of OCD in first-degree relatives of 74 OCD probands. A statistical comparison between OCD probands with and without familial loading was performed using Pearson's chi(2) test, Fisher's exact test, or Student's t test when appropriate. The rate of OCD was 3.5% in directly interviewed first-degree relatives, Eleven percent of the probands had at least one family member with OCD. There were no differences between the two types of OCD (familial vs. non-familial) except for life events prior to the onset of OCD, which were more common and more severe in non-familial OCD subtypes. In conclusion, our results (1) confirm that there is a familial component in the expression of some forms of OCD and (2) indicate that familial OCD patients are not characterized by peculiar clinical features, but appear to have a lower threshold for precipitating events. Copyright (C) 2002 S. Karger AG, Basel.