Recent work on the empirical structure of psychopathology has aimed to address some limitations that can arise from traditional categorical classification approaches. This research has focused on modeling patterns of co-occurrence among traditional diagnoses, uncovering a variety of well-validated dimensions (or spectra) of psychopathology, spanning common and uncommon mental disorders. A model integrating these empirically derived spectra (the Hierarchical Taxonomy of Psychopathology; HiTOP) has been proposed. However, the placement of obsessive-compulsive disorder (OCD) within this model remains unclear, as studies have variably found OCD to fit best as part of the Fear, Distress or Thought Disorder spectra. One reason for this may be the heterogeneity of symptoms experienced by individuals with OCD, which is lost when analysing categorical diagnoses. For example, different symptom clusters within OCD—such as washing and contamination versus obsessions and checking—may be differentially associated with different spectra in the HiTOP model. The aim of this study was to test this hypothesis. Data were collected in an anonymous online survey from community participants (n = 609), largely with elevated symptoms of mental illness, and analyzed in a factor analytic framework treating OCD as a unitary construct and as four separate symptom clusters. The results indicated that OCD and its constituent symptom clusters had significant loadings of varying strength on the Fear and Thought Disorder spectra. These findings suggest that OCD may be best characterized as cross-loading on both the Fear and Thought Disorder spectra, and highlight the importance of accounting for diagnostic heterogeneity in future research.
