We calculated Morbidity Risks (MR%) for the major psychiatric conditions in the families of three groups of patients, affected by Eating Disorders (ED; n = 41), Obsessive Compulsive Disorder (OCD; n = 70) and Mood Disorders (MD; n = 39). Our aim was to verify the hypothesis of a common familial pattern of aggregation. Familial risk of developing OCD was significantly increased in the families of OCD probands. Homotypic cases were also augmented in ED and MD families with respect to the rates of the general population, although without statistical significance in the crosswise comparisons. These results confirm the existence of a genetic susceptibility to the development of OCD.
