University of Queensland researchers have demonstrated that semaglutide, the active component in weight-loss drugs Ozempic and Wegovy, is safe and highly effective for weight loss in people with schizophrenia without compromising their mental health treatment. The 36-week investigator-led trial provides world-first evidence addressing a critical unmet need in this vulnerable population.
Significant Weight Loss Without Psychiatric Complications
The study found that participants receiving semaglutide lost almost 14 percent of their bodyweight across the trial period, compared to those taking placebo. Professor Dan Siskind, who led the research, emphasized the clinical significance of these results for patients who often discontinue essential psychiatric medications due to weight-related side effects.
"Before this study, we did not know if there would be drug-to-drug interactions with semaglutide or any impact on mental state," Professor Siskind explained. "We were able to show that semaglutide didn't affect psychotic symptoms or levels of anti-psychotic medications, indicating that it doesn't worsen their psychosis. We found no increased risk or drug interactions."
The research also revealed improvements in body composition, with the lean mass to fat mass ratio improving in the semaglutide group, suggesting more fat was lost than non-fatty tissues such as muscle.
Addressing Critical Health Disparities
People with schizophrenia face a 16-year life expectancy gap compared to the general population, driven largely by obesity-related illnesses. This disparity is exacerbated by antipsychotic medications, which are associated with significant weight gain in patients.
"Anti-psychotic medications are associated with high weight gain in patients, leading to poorer quality of life, shorter life expectancy, and poorer medication adherence," Professor Siskind noted. He highlighted that patients often stopped taking prescribed medication clozapine specifically because of weight gain, making these findings particularly relevant for clinical treatment guidelines.
Implications for Treatment Access
The study was investigator-led with no pharmaceutical company involvement, lending credibility to the findings published in Lancet Psychiatry. However, access remains a significant barrier, as semaglutide is not currently listed on Australia's Pharmaceutical Benefits Scheme (PBS) for weight loss.
Professor Siskind, who works clinically as a psychiatrist at Metro South Addiction and Mental Health Services in Brisbane, advocates for policy changes to improve access. "People with schizophrenia urgently need access to effective treatments for obesity, such as semaglutide," he said. "We would be strongly advocating for access to PBS listing for semaglutide for this population."
The researcher noted that many people with schizophrenia cannot afford to pay for the medication out of pocket, though some patients currently use semaglutide for weight loss with family financial support. The findings provide crucial evidence that could inform future treatment guidelines and reimbursement decisions for this underserved population.
