Obsessive-compulsive disorder subtypes: an attempted replication and extension of a symptom-based taxonomy.

A symptom-based subgroup taxonomy for obsessive-compulsive disorder (OCD) was evaluated and refined. The Yale-Brown Obsessive-Compulsive Scale symptom checklist was scored and cluster analysis was conducted with a sample of OCD patients (N = 114). Results were compared to Calamari et al.'s (Behaviour Research and Therapy 37 (1999) 113) five subgroup model. Rules for determining the number of subgroups supported a more complex model. In between sample comparisons, a stable contamination subgroup was found in both a five and seven subgroup taxonomy. Between sample stability was not as strong for Harming, Obsessionals, Symmetry, and Certainty subgroups. Hoarding, as a distinctive subgroup, was unstable in separate samples. When the Calamari et al. sample and the present sample were combined (N = 220), we found a reliable Hoarding subgroup. More interpretable and stable models emerged with the combined samples suggesting that large clinical samples are needed to identify OCD subgroups. Greater support was found for a seven subgroup taxonomy based subgroup interpretability and validation measure differences. The potential utility of symptom-based subgroup models of OCD and alternative approaches are discussed. Identification of reliable and valid OCD subtypes may advance theory and treatment.