Morbidity risk for obsessive-compulsive spectrum disorders in first-degree relatives of patients with eating disorders.

OBJECTIVE A hypothesis that eating disorders are a phenomenological variant of obsessive-compulsive disorder (OCD) has been proposed. This study was conducted to determine whether anorexia nervosa and bulimia, the two main eating disorders, are familial and whether the risk for obsessive-compulsive spectrum disorders (OCD and tic disorders) is higher in families of patients with eating disorders. METHOD The morbidity risk for obsessive-compulsive spectrum disorders in first-degree relatives of 136 female probands with eating disorders (84 with anorexia nervosa, 52 with bulimia) was compared to that for first-degree relatives of 72 female comparison subjects. RESULTS The morbidity risk for obsessive-compulsive spectrum disorders was significantly higher among the 436 relatives of the eating disorder probands than among the 358 relatives of the comparison subjects (9.69% versus 0%). This finding was independent of any comorbid diagnosis of an obsessive-compulsive spectrum disorder in the eating disorder probands. The eating disorder group and the comparison group did not differ in familial risk for eating disorders and tic disorders. CONCLUSIONS To better understand the genetic components of eating disorders, these disorders should be considered as part of the obsessive-compulsive spectrum of disorders.