This study attempted to determine whether Anorexia nervosa (AN), Bulimia nervosa (BN) and Obsessive Compulsive Disorder (OCD) share clinical and psychopathological traits.

The sample consisted of 90 female patients (30 OCD; 30 AN; 30 BN), who had been consecutively referred to our Unit. All subjects met DSM-IV criteria for those pathologies. The assessment consisted on the Maudsley Obsessive-Compulsive Inventory, Questionnaire of obsessive traits and personality by Vallejo, Eating Attitudes Test-40, Eating Disorder Inventory, and Beck Depression Inventory. ANCOVA tests (adjusted for age and body mass index) and multiple linear regression models based on obsessive-compulsiveness, obsessive personality traits and perfectionism, as independent variables, were applied to determine the best predictors of eating disorder severity.

ANCOVA revealed several significant differences between obsessive-compulsive and eating disordered patients (MOCI, p < 0.001; EAT, p < 0.001; EDI, p < 0.001), whereas some obsessive personality traits were not eating disorder-specific. 16.7% OCD presented a comorbid eating disorder, whereas 3.3% eating disorders had an OCD diagnosis. In the eating disorder group, the presence of OC symptomatology was positively associated (r = 0.57, p < 0.001) with the severity of the eating disorder. The results were maintained after adjusting for comorbidity.

Although some obsessive-compulsive and eating disorder patients share common traits (e.g. some personality traits especially between OCD and AN), both disorders seem to be clinically and psychopathologically different.