An observational South Korean study has found that adults who took prescription weight-loss medication in the past year reported higher rates of depression, mental-health counselling and suicidal thoughts than those who did not, with the associations strongest among users who gained or regained weight. Researchers say the findings, while notable, cannot prove that the drugs directly cause these effects, and experts caution that the data largely predate the newer GLP-1 medications now widely used, such as Wegovy and Mounjaro.

The study, conducted at Asan Medical Center and published in the Korean Journal of Family Practice on 23 August, examined 27,741 adults, of whom 846 had taken weight-control medication in the previous year. Users were 1.9 times more likely to experience depression, twice as likely to seek mental-health counselling, 2.7 times more likely to report suicidal thoughts and 1.7 times more likely to attempt suicide; those who gained weight despite taking the drugs had 4.2 times higher odds of suicidal ideation. Experts noted the data, collected between 2013 and 2022, mainly reflect older anti-obesity drugs such as phentermine and topiramate rather than modern GLP-1 agents, and that the study cannot separate pre-existing mental-health conditions from new symptoms, meaning further research is needed to clarify any causal link.