Symptom-based subtypes of obsessive-compulsive disorder.

Abstract

Obsessive-compulsive disorder (OCD) is heterogeneous in its presentation and quests to clarify the best way to subtype OCD have remained elusive. This thesis aims to assess for symptom-based OCD subtypes in a sample of patients with OCD and to describe the characteristics of these OCD symptom subtypes. The methods used include principal components analysis of the results of the Yale-Brown Obsessive-Compulsive Disorder Scale – Symptom Checklist (YBOCS-SC) and the Vancouver Obsessional Compulsive Inventory (VOCI) self report obtained from a sample of 154 subjects with a primary diagnosis of OCD. Five symptom factors explained 67.9% of the variance. They were named: 1) hoarding; 2) contamination/cleaning; 3) symmetry/ordering; 4) unacceptable/taboo thoughts; and 5) doubt/checking. These factors were used as predictors of a number of systematically chosen characteristics and were subject to regression analyses. Results indicated that different OCD symptoms predicted different phenomenological characteristics, degrees of comorbidity, and different cognitive and emotional correlates. Results also indicate that psychological forms of therapy should be tailored to the patient’s prominent OCD symptoms. The study supported 5 major symptom dimensions rather than four. In particular, it revealed significant differences between unacceptable/taboo thoughts and doubt/checking. The results encourage researchers using symptom-based subtypes to continue their efforts with the hope of improving our understanding of the aetiology of these symptoms and the treatments that we provide patients with these symptoms.