Core Dimensions Predict Manifest Symptom Expression in a Community Sample With Obsessive‐Compulsive Disorder

High symptom heterogeneity in obsessive-compulsive disorder (OCD) confounds clinical and research progress. Two notable models organize symptoms dimensionally. The first is a four-factor model describing manifest symptoms related to germs/contamination, harm/injury/bad luck, unacceptable thoughts and symmetry. The second describes two core emotional-motivational dimensions of harm avoidance (HA) and incompleteness (INC). Research comparing these models has typically been limited by the use of measures that either do not assess manifest symptoms using the four-factor model framework or do not adequately support continuous dimensional scoring. Utilizing a voluntary, non-incentivised adult community sample with lifetime OCD diagnoses, this study explored relationships between both models using measures purposefully designed to assess each, and that employ comparable dimensional operationalizations-the Dimensional Obsessive-Compulsive Scale and the Obsessive-Compulsive Core-Dimensions Questionnaire-Trait. Regression analyses showed HA and INC to be moderate predictors of overall symptom severity and unique predictors of different manifest symptom dimensions. HA predicted symptoms relating to harm/injury/bad luck and unacceptable thoughts, whereas INC predicted symptoms relating to germs/contamination and symmetry. Our findings indicate that the core dimensions help to explain and organize patterns in OCD symptom heterogeneity and add to the growing evidence that they are candidate endophenotypes. To our knowledge, this is the first study to examine associations of the manifest symptom and core dimension models in a community sample of individuals with lifetime OCD. Conceptual and clinical implications, including those of continued refinement of symptom models for OCD, are discussed.