Objective: To determine the prevalence and clinical significance of obsessive-compulsive (OC) symptoms among a group of stable outpatients with schizophrenia.
Methods: We studied 118 patients with schizophrenia from an urban clinic, characterized using clinical symptoms scales, including the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), and neuropsychological testing. We categorized patients into three groups according to severity of OC symptoms and used multivariate linear regression and chi-square tests to compare groups on variables of interest.
Results: Only 10 patients (8.8%) had Y-BOCS scores greater than 16, a standard criterion for OCD studies. The patient group with the most OC symptoms (Y-BOCS scores >11) scored higher on the Hamilton Depression Scale, the positive symptoms subscale of the Positive and Negative Syndromes Scale (PANSS) and its delusions item, but not on any of the neuropsychological tests compared to the other two groups. Patients with most severe compulsive symptoms (but not OC symptoms together, or obsessions alone) were more likely to be treated with olanzapine or clozapine, atypical antipsychotic medications previously reported to induce or worsen OC symptoms.
Conclusions: Our results confirm previous findings that patients with schizophrenia and comorbid OC symptoms have more positive symptoms but not the suggestion that such patients are more cognitively impaired than their counterparts without OC symptoms. We suggest possible explanations for discrepancies in the literature, including differences in patient sampling and definition of comorbid OC symptoms. Finally, our data suggest that olanzapine and clozapine may produce or worsen compulsions in some patients; prospective studies need to address this possibility.