Obsessive-compulsive symptoms (OCS) experienced by patients with a diagnosis of obsessive-compulsive disorder (OCD) and schizophrenia

Obsessive-compulsive symptoms (OCS) have been noted in a significant portion of patients with schizophrenia. Currently, there are limited studies involving patients with both obsessive-compulsive disorder (OCD) and schizophrenia which compare their clinical characteristics with those of patients with OCD without schizophrenia. This project aims to investigate the most common OCS experienced by patients with a diagnosis of both schizophrenia and OCD in comparison to those experienced by patients with OCD without schizophrenia. This retrospective cohort study involved patients referred to the Western Sydney Obsessive-Compulsive and Related Disorders Service. The likelihood of a patient with either OCD without schizophrenia or OCD with schizophrenia presenting with a subtype of OCS was assessed using a series of multiple logistic regression models which were adjusted for demographic variables. Model results were presented as odds ratios (OR) and 95% confidence intervals (CI). Within the cohort of 99 patients, one third had a diagnosis of schizophrenia or related disorders. When adjusted for age, sex, marital status, education, employment, and Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) assessment, the group of patients with co-occurring schizophrenia were more likely to experience aggressive, religious, and miscellaneous obsessions and checking compulsions. However, they were less likely to present with contamination obsessions and cleaning compulsions. This study reports the OCS that are more commonly associated with patients with both OCD and schizophrenia compared to OCD alone within a clinical sample. Future areas of research include performing a similar logistic regression analysis process on a larger cohort to allow for more symptom models to converge.