摘要:Aim : the aim of the study is to evaluate the socio-demographic and clinical features with prognostic value in predicting evolution in severe OCD. Materials and methods: patients with a main diagnosis of OCD were recruited according to DSM-IV criteria. Socio-demographic and clinical features were assessed by mean of a semi-structured interview and clinical rating scales (Y-BOCS, HAM-A, HAM-D and SCID-II). Two subgroups were compared according to the severity of symptoms (severe vs mild-moderate). Results: the total sample was made up of 450 OCD subjects aged 34.5±12.1, with a mean age of onset 22.3±9.1; 215 subjects (47.8%) were females. Patients with severe OCD (Y-BOCS ≥ 32) showed a more insidious onset and a more chronic course compared to patients with mild-moderate symptoms. Other predictors of increased OCD severity were washing and hoarding compulsions. Lastly, the severity of the obsessive-compulsive condition was higher when it was associated either with mood disorders or with Axis II disorders (particularly Cluster A). Discussion: our study shows a correlation between severe OCD and severity predictors such as functional impairment and mood disorders. Furthermore washing and hoarding symptoms, lifetime comorbity with mood disorders and Cluster A personality disorders seem to predict OCD severity.