The relationship of obsessive-compulsive disorder to possible spectrum disorders: Results from a family study

Background: The familial relationship between obsessive-compulsive disorder (OCD) and "obsessive-compulsive spectrum" disorders is unclear: This study investigates the relationship of OCD to somatoform disorders (body dysmorp hic disorder [BDD] and hypochondriasis), eating disorders (e.g., anorexia n ervosa and bulimia nervosa) pathologic "grooming" conditions (e.g., nail bi ting, skin picking, trichotillomania), and other impulse control disorders (e.g., kleptomania, pathologic gambling, pyromania) using blinded family st udy methodology. Methods: Eighty case and 73 control probands, as well as 343 case and 300 c ontrol first-degree relatives, were examined by psychiatrists or Ph.D. psyc hologists using the Schedule for Affective Disorders and Schizophrenia-Life time Anxiety version. Two experienced psychiatrists independently reviewed all diagnostic information and made final consensus diagnoses using DSM-IV criteria. Results: Body dysmorphic disorder, hypochondriasis, any eating disorder, an d any grooming condition occurred more frequently in case probands. In addi tion, BDD, either somatoform disorder and any grooming condition occurred m ore frequently in case relatives, whether or not case probands also had the same diagnosis. Conclusions: These findings indicate that certain somatoform and pathologic grooming conditions are part of the familial OCD spectrum. Though other "s pectrum" conditions may resemble OCD, they do not appear to be important pa rts of the familial spectrum. (C) 2000 Society of Biological Psychiatry.