A new study from South Korea has found a striking association between prescription weight-loss medication and suicidal thoughts, particularly among those who regained weight after stopping the drugs. Researchers analyzed data from over 27,000 adults who participated in a national health survey between 2013 and 2022, and the findings were published in the Korean Journal of Family Practice.
The study, led by Dr. Son Ki-young of Asan Medical Center, compared 846 people who had used prescription diet pills in the past year with nearly 27,000 who had not. Overall, those who used the medications were 2.7 times more likely to report suicidal thoughts, 1.9 times more likely to have made a suicide plan, and 1.7 times more likely to have attempted suicide. They also reported higher rates of prolonged depression and mental health counseling.
The most alarming figures emerged from a subgroup: individuals who took the medication and still gained weight. Their odds of suicidal thoughts were 4.2 times higher than those who never used the drugs. Depression and counseling rates were also elevated, at roughly 1.9 and 1.8 times higher, respectively.
The researchers cautioned that the link is not purely pharmacological. “The increase in suicide-related index, among those who regained weight after weight-loss medication, is not just related to the neurological and psychiatric effects of the medicine itself,” they wrote. “It is likely to be connected in a complex way to the psychological and social elements related to failing to control one’s weight.”
This study is observational, meaning it cannot prove causation. The survey period also predates the widespread use of newer GLP-1 drugs like semaglutide (Wegovy) and tirzepatide (Zepbound, Mounjaro) in South Korea. Instead, the sample largely reflects older appetite suppressants such as phentermine, diethylpropion, phendimetrazine, topiramate, and orlistat—stimulant-based drugs already linked to anxiety, insomnia, and mood changes.
People with severe obesity already face higher baseline rates of depression and body-image distress, which complicates the interpretation. A one-time survey cannot distinguish between preexisting symptoms and new ones. This is a known limitation of such cross-sectional research.
Notably, in January, the U.S. Food and Drug Administration (FDA) asked drugmakers to remove suicidal-ideation warnings from the labels of Saxenda, Wegovy, and Zepbound after a review of 91 placebo-controlled trials involving more than 107,000 patients found no increased risk of suicidal thoughts or behavior linked to GLP-1 drugs. Both Novo Nordisk and Eli Lilly supported the FDA’s findings, though Lilly’s consumer materials still advise patients to watch for mood changes and contact a doctor if symptoms are “new, worse or worry you.”
The South Korean findings add to the ongoing debate about the mental health effects of weight-loss medications. While the FDA has cleared GLP-1 drugs, the psychological impact of weight regain—whether from drug discontinuation or treatment failure—remains a critical area of concern. For more on the broader implications, see the surge in GLP-1 use among children and semaglutide's potential brain effects.
Experts emphasize that weight loss is not just a physical journey but a psychological one. The stigma and frustration of regaining weight can be profound, and this study suggests that clinicians should monitor patients for mental health changes, especially if they experience weight regain after using prescription diet aids.
