REVIEW OF: Chandradasa M et al, Asian J Psychiatr 2022;68:102963

STUDY TYPE: Randomized placebo-controlled trial

People with schizophrenia have higher rates of cardiometabolic mortality. There is meta-analytic evidence that adjunctive topiramate reduces weight and improves psychiatric symptoms in schizophrenia. However, there are few studies of this medication in patients from South Asia, who are inherently more vulnerable to cardiometabolic disturbances. This study investigated topiramate’s effects on weight and psychiatric symptoms in this population.

This was a randomized, double-blind, placebo-controlled trial of topiramate in 100 patients from Sri Lanka with a BMI >25 who had been on an antipsychotic for at least a year (mean age 41). Patients were treated with either topiramate (titrated to 50 mg twice daily) or placebo, in addition to their current antipsychotic, for three months. Weight and psychopathology (using the Brief Psychiatric Rating Scale [BPRS], baseline mean 24.3) were assessed monthly. All of the subjects completed the trial.

After three months, there was significantly greater weight reduction (-6.6 lbs vs +0.7 lbs) and improvement in BPRS score (-1.6 vs +0.3) in the topiramate group. Topiramate had a significantly higher prevalence of appetite loss (12% vs 0%); otherwise, there were no differences in adverse effects. The number needed to treat for a 5% body weight reduction was 4.

Potential limitations include that many patients were on antipsychotic polypharmacy, and that the dose of topiramate was relatively low. The authors also did not measure glucose, hemoglobin A1c, or lipids. Furthermore, all subjects were stable outpatients with chronic schizophrenia. Therefore, the generalizability of the findings to other patients and phases of illness is limited. Nevertheless, the authors studied topiramate in a resource-limited, vulnerable patient population.

CARLAT TAKE

Adjunctive topiramate significantly reduced weight and psychopathology in schizophrenia-stable outpatients in South Asia, consistent with previous meta-analyses. Further studies of optimal dosage are needed, but findings support the clinical utility of topiramate as a viable off-label treatment in this patient population.