Clinical investigation of the ICD-10 subcategories for obsessive-compulsive disorder

To examine the validity of ICD-10 subcategories for obsessive-compulsive disorder (OCD), the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) was applied to 53 OCD patients. The ratios of Y-BOCS compulsions subscore to obsessions subscore were calculated. The group with ratios around one consisted of patients diagnosed in three subcategories (F42.0, F42.1 and F42.2). This suggests that subjective subcategorization such as ICD-10 may be inadequate to differentiate between predominantly obsessive and compulsive patients compared with differentiation by quantitative assessment such as the Y-BOCS ratio. Thus, in selecting the appropriate therapeutic methods, we emphasize the usefulness of quantitative assessment in clinical settings.