Psychopharmacology and Psychiatry Updates Semaglutide for Clozapine-Induced Weight Gain: The COaST Trial
Feb 25, 2026
Oliver Freudenreich, psychiatrist and psychopharmacology expert, breaks down the COaST trial on semaglutide for clozapine-related weight gain. He walks through study design, striking weight-loss results, safety signals and practical barriers to prescribing. Short, clear takes on what the trial shows and what still needs more research.
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Patient Story Of Clozapine Success And Weight Crisis
- Josephine is a 42-year-old with schizophrenia who improved on clozapine but gained 65 pounds and considered stopping the medication.
- This clinical vignette illustrates the real-world tradeoff between clozapine's efficacy and severe metabolic side effects that threaten adherence.
Weight Gain From Antipsychotics Drives Premature Mortality
- Antipsychotic-induced weight gain contributes substantially to a 15–20 year reduced life expectancy via cardiovascular disease.
- Managing metabolic effects of drugs like clozapine is thus not cosmetic but a critical mortality intervention for patients with severe mental illness.
COAST Trial Design And Supply Limitations
- The COAST trial randomized 31 obese clozapine-treated patients to weekly semaglutide 2 mg versus placebo over 36 weeks, but supply shortages forced a lower dose and early termination.
- Limited enrollment and 2 mg dosing were trial constraints that affect generalizability and power.