Two dimension-based models have emerged that capture the high symptom heterogeneity observed in obsessive-compulsive disorder (OCD)—one grouping symptoms by their overt presentation, the other identifying core dimensions of underlying symptom motivations. This paper presents two studies that explore (1) the relationship between these two models, and (2) the stability of the models and dimensions they each represent. Study 1 found that the core dimension motives jointly predicted overall OCD symptom severity, and that each core dimension further predicted unique nonoverlapping overt symptom dimensions. Study 2 demonstrated that despite high instances of item-level symptom change, both models and their respective dimensions were longitudinally stable, with exception to overt symptoms relating to harm/injury/bad luck. Both studies support further consideration of these models as clinical resources and support the candidacy of the core dimensions as endophenotypes for OCD. Results, limitations, clinical implications, and future directions are discussed.
Author Keywords: Core Dimensions, Endophenotype, Obsessive-Compulsive Disorder, Overt Symptoms, Stability, Symptom Models