Sleep and mood after starting GLP-1 drugs

Researchers in Turkey followed 78 adults with obesity for three months after they started tirzepatide or semaglutide, and reported something that cuts against a worry that has circulated for two years: sleep and mood scores moved in the better direction, not the worse one. The study, led by Yasemin Kir and colleagues and published August 18, 2026 in the Journal of Endocrinological Investigation, is a real-world look at both measures together in the same group of patients starting GLP-1 based therapy for obesity^[1].

What the researchers measured

The team enrolled patients starting a GLP-1 based therapy at an endocrinology clinic. Fifty-two started tirzepatide, a dual GIP and GLP-1 receptor agonist, and twenty-six started semaglutide, a GLP-1 receptor agonist alone. At baseline and again at three months, everyone completed the Patient Health Questionnaire-9 (PHQ-9, a nine-item depression screening tool) and the Pittsburgh Sleep Quality Index (PSQI, a self-reported sleep-quality questionnaire covering the past month). Median PHQ-9 scores fell from 10.0 to 6.0, and the share of patients scoring in the clinically significant depression range dropped from 55.1% to 11.5%^[1]. Median PSQI scores fell from 6.0 to 3.0, and the share reporting poor sleep quality dropped from 55.1% to 16.7%^[1]. Neither the amount of weight lost nor the choice between tirzepatide and semaglutide was associated with how much a patient's scores improved^[1].

What this observational design cannot show

None of that proves tirzepatide or semaglutide treats depression or insomnia directly. The study had no placebo group and no comparison arm, so there is no way to know how much of the change would have happened anyway once someone commits to a structured weight-management program. Seventy-eight patients over three months is a short window for a mood measure that moves for many reasons unrelated to any medicine, and every score in the study came from a self-report questionnaire rather than a clinical interview. People who start a weight-loss medication and see early results often feel better about several things at once: less joint pain, fewer nights disrupted by reflux or breathing trouble, more confidence in daily life, closer follow-up with a clinician than before treatment started. Any one of those could move a PHQ-9 or PSQI score on its own. Kir and colleagues describe their own findings as short-term and observational, and that framing matters more than the topline percentages. A better night's sleep and a lower depression score after starting a weight-loss drug is an encouraging early signal worth following into a larger trial with a comparison group. It is not proof that the drug works as an antidepressant.

The mood safety signal regulators already reviewed

The opposite worry, that GLP-1 drugs might raise the risk of suicidal thoughts, already went through a formal regulatory review on both sides of the Atlantic. The European Medicines Agency's Pharmacovigilance Risk Assessment Committee opened an inquiry in July 2023 after case reports of suicidal and self-injurious thoughts in people using liraglutide and semaglutide, then examined roughly 150 individual reports alongside clinical-trial and post-marketing data for the wider GLP-1 receptor agonist class. In April 2024 the committee concluded that the available evidence does not support a causal association between GLP-1 receptor agonists and suicidal or self-injurious thoughts and actions, and that no change to the product information was warranted^[2]. A 2025 pooled analysis of four trials in Diabetes/Metabolism Research and Reviews reached a similar reading, a risk ratio of 0.57 with a wide confidence interval, though the authors flagged high variation between the trials and recommended continued monitoring in patients with a pre-existing psychiatric history^[3]. The FDA arrived at the same place on January 13, 2026: a meta-analysis of 91 placebo-controlled trials covering 107,910 patients, 60,338 of them on a GLP-1 drug, found no increased risk of suicidal thoughts or behavior, and a separate FDA Sentinel System cohort study of more than two million new users found no increased risk of intentional self-harm either. The agency asked manufacturers to remove the suicidal-ideation warning from the labels of Wegovy (semaglutide), Zepbound (tirzepatide) and Saxenda (liraglutide), while telling clinicians to keep asking patients about new or worsening mood symptoms regardless^[4]. Two agencies, three separate reviews, one direction of travel: the drugs that carried a suicidal-thoughts warning are having that warning removed, not strengthened. That is a different question from whether the same drugs improve mood, and the two should not be collapsed into one story.

What this means if you are starting a GLP-1 drug

Put the two threads side by side and the picture is more careful than either headline alone suggests. Early, observational data from one clinic hint that sleep and mood measures often improve alongside weight loss on tirzepatide or semaglutide. Two rounds of formal pharmacovigilance review have found no signal that these drugs raise suicide risk, and regulators have started removing the warning language tied to that opposite worry. Neither conclusion means a GLP-1 drug will fix a mood problem, and neither is a reason to start or stop treatment without a clinician. If you already live with depression, anxiety, or another mental-health condition and you are weighing tirzepatide or semaglutide, bring that history to the prescriber managing your care, alongside the safety detail on our tirzepatide and semaglutide pages. Ask specifically how the practice monitors mood during the first months of treatment, since that is the window this new study covered and the one the regulatory reviews scrutinized most closely.