Abstract
Obsessive-compulsive disorder (OCD) is a heterogenous condition involving intrusive thoughts and functionally associated rituals across multiple domains (e.g., symmetry, contamination). One approach to disentangle the heterogeneity of OCD has been to examine underlying motivations that influence OCD’s diverse observed symptoms. One such motivation is the experience of sensory phenomena, which capture a sense that things are incomplete or “not just right.” Though 60 to 80% of patients experience sensory phenomena, they remain absent from cognitive-behavioral models of OCD, in part because their latent structure and relationship to symptoms remain poorly understood. The following manuscripts characterize the structure, influence, and biobehavioral correlates of sensory phenomena. In Paper 1, we applied latent variable approaches to evaluate the multidimensionality of a measure of sensory phenomena, as well as its utility in parsing heterogeneity in OCD patients (n = 993). Confirmatory factor analysis supported a six-factor model, and latent class analysis suggested four patient subgroups based on sensory phenomena. In Paper 2, we used network analysis to test associations of sensory phenomena with both the core features (i.e., obsessions and compulsions) and symptom dimensions of OCD. Network results indicated that patients high in sensory phenomena displayed weaker functional relationships between obsessions and compulsions. Symmetry and washing had the greatest increase in variance explained when sensory phenomena were included in the network. In Paper 3, we sought to characterize neuropsychological functions relevant to sensory phenomena through supervised machine learning. Random forest best differentiated between healthy controls and patients with/without sensory phenomena, and patients without sensory phenomena exhibited greater risk sensitivity compared to healthy controls. Taken together, results support the notion that accounting for sensory phenomena—and their multidimensionality—can inform heterogeneity in OCD symptom presentations.