No Confirmed Link Between Clozapine, Obsessive-Compulsive Symptoms in Schizophrenia

Further research could result in a clozapine-level threshold that would warn clinicians about the possibility of developing obsessive-compulsive symptoms in schizophrenia.

The following article is part of conference coverage from the 2019 American Psychiatric Association Annual Meeting (APA 2019) in San Francisco, CA. Psychiatry Advisor’s staff will be reporting breaking news associated with research conducted by leading experts in psychiatry. Check back for the latest news from APA 2019.

SAN FRANCISCO — Individuals with schizophrenia and obsessive-compulsive symptoms (OCS) did not demonstrate differing levels of clozapine from those with schizophrenia alone. This research was recently presented at the American Psychiatric Association Annual Meeting, held May 18-22, 2019, in San Francisco, California.

Related Articles

This retrospective, descriptive study included 45 individuals with schizophrenia and schizoaffective disorder, all of whom were treated with clozapine. The participants were followed in 2 Catalonian outpatient clinics. The primary outcome was the association between plasma clozapine levels and the presence of obsessive-compulsive symptoms.

Obsessive-compulsive symptoms were present among 22.2% (n=10) of the study participants. Of the participants, 80.0% were men, and 95.5% were Spanish with a mean age of 41.5 years. Plasma clozapine levels were higher among those with comorbid obsessive-compulsive symptoms (470.6±180.5 with a clozapine dose of 343.7±227.4) compared with those without (381.4±207.3 with a clozapine dose of 340.4±161.2). These results were not statistically significant (P >.05).

Researchers noted that there was not “any significant difference in [clozapine] between both groups, [but] this could be due to the small size of [the] sample. Comparing our results to the literature, we found heterogeneous results: some studies support a positive correlation between [clozapine] and the presence and severity of OCS and others don’t.”

“[Having] a laboratory threshold that [warns] the clinician about the possibility of developing OCS could be very useful. Adequate recognition of OCS in schizophrenia could avoid additional suffering as it may respond well to treatment,” researchers wrote. “Further research is needed to understand the correlation, the mechanism, and the pathophysiology underlying this co-morbidity.”

For more coverage of APA 2019, click here.


Berengue MR, Ramirez MM. Correlating plasma levels of clozapine with the risk of developing obsessive-compulsive symptoms. Poster presented at: American Psychiatric Association Annual Meeting; May 18-22, 2019; San Francisco, CA. Abstract 42.