A Multidimensional Model of Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is a clinically heterogeneous condition. This heterogeneity can reduce the power and obscure the findings from natural history studies to genome scans, neuroimaging, and clinical trials. The authors review the evidence supporting a multidimensional model of OCD. METHOD: Computerized and manual literature searches were performed to identify factor-analytic studies of obsessive-compulsive symptoms before data from disciplines that bear on the potential usefulness of these dimensions were considered. Selection criteria included the novelty and importance of studies and their relevance to outcomes of interest to well-informed mental health professionals.

Twelve factor-analytic studies involving more than 2,000 patients were identified that consistently extracted at least four symptom dimensions: symmetry/ordering, hoarding, contamination/cleaning, and obsessions/checking. These dimensions were associated with distinct patterns of comorbidity, genetic transmission, neural substrates, and treatment response. The evidence supporting the hoarding dimension is particularly robust.