Efficacy and safety of semaglutide versus placebo for people with schizophrenia on clozapine with obesity (COaST): a phase 2, multi-centre, participant and investigator- blinded, randomised controlled trial in Australia

What Was Tested

Researchers studied Semaglutide in this randomized controlled trial publication.

Glucagon-like peptide-1 receptor agonists, including semaglutide, contribute to substantial weight loss in the general population, but their effect and safety profile in people with schizophrenia remain unknown.

National Health and Medical Research Council, Qld Advancing Clinical Research Fellowship, and Metro South Health Research Support Scheme Program.

Who Took Part

PubMed indexes the participants as teenagers, young adults, adults and middle-aged adults, both men and women.

The primary outcome was percentage body weight change, analysed using a mixed model for repeated measures, at 36 weeks post-baseline assessment.

All investigators and participants were masked to medication allocation.

How the Study Was Run

The design is described as randomized, double-blind and placebo-controlled.

Random assignment meant chance, not the researchers, decided who got Semaglutide and who got the comparison, which limits bias.

Neither the participants nor the staff measuring them knew who was on Semaglutide, so expectations could not easily colour the readings.

Some participants received a placebo instead of Semaglutide, giving a reference point.

Secondary measures included clozapine and norclozapine concentrations and psychosis symptoms as measured by the Positive and Negative Syndrome Scale (PANSS).

What Was Measured

PubMed files the paper under topics including Australia, Glucagon-Like Peptides, Clozapine, Antipsychotic Agents, Obesity, Schizophrenia and Weight Loss.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of Semaglutide.

Its findings take up roughly 9 sentences of the abstract and are left out here on purpose; the source paper is the place to read them.

The publication is from 2025 (The lancet. Psychiatry), a journal based in England.

More context: the Semaglutide compound page, all human trials.