Obesity Associated With Symptomatic Remission in Clozapine-Treated Individuals With Treatment-Resistant Schizophrenia

Clozapine, indicated for use in treatment-resistant schizophrenia (TRS), comes with notable weight gain and metabolic side effects. Prior studies have suggested a link between weight gain and antipsychotic efficacy in schizophrenia. In this study, we seek to explore the relationship between obesity and clinical outcome in TRS on clozapine treatment.

This study was conducted at a tertiary mental health institution on patients with TRS on clozapine for at least 12 weeks. Data were collected through a research interview and review of medical records. Symptoms were assessed on the Positive and Negative Syndrome Scale. Anthropometric measures, including weight, height, waist circumference and blood pressure, were measured during the visit. A blood sample for lipids and glucose was obtained after an 8-hour fast.

One hundred Fifty-four patients on clozapine were identified and included in the final analysis. Thirty-seven patients (24.0%) achieved symptomatic remission. The remitter group had a significantly higher body mass index (BMI) compared with the nonremitter group (26.6 vs 24.2 kg/m 2 , P = 0.007). Univariate analyses identified BMI, waist circumference and blood pressure as possible metabolic factors associated with remission. In the multivariate model, BMI was the only statistically significant predictor of remission status (OR = 1.147, P = 0.020).

Our study found that obesity was associated with remission in TRS patients on clozapine. This lends support to the metabolic threshold for clozapine. Further investigations are needed to study the mechanisms underpinning weight gain and clozapine efficacy.