Glucagon-like peptide-1 (GLP-1) agonists have been successfully used in clinical practice for the treatment of diabetes and obesity, offering significant clinical benefits. However, concerns regarding their potential link to psychiatric side effects, like suicidal thoughts and behaviours (STB) have emerged. This narrative review investigates the complex interplay between GLP-1 agonists and STB, focusing on the biological stress induced by rapid weight loss, psychological and social consequences, similar mechanism with addiction, and the evaluative lens of the Bradford Hill criteria on causality. While GLP-1 agonists can contribute to substantial health improvements, they also introduce biological and psychological stressors. Disruptions in homeostasis from quick weight reduction can elevate cortisol and norepinephrine levels, heightening the risk for, or exacerbation of STB. Psychological factors, including unfulfilled expectations and identity changes after significant weight loss, compound these risks. Utilizing the Bradford Hill criteria reveals insufficient evidence for a direct causal link between GLP-1 agonists and STB. Yet, the indirect effects related to the metabolic and psychological disturbances associated with rapid weight loss call for a cautious approach. Used carefully in targeted populations GLP-1 agonists may even emerge as protective agents against STB. Therefore, it is crucial to monitor patients during the treatment and screen for preexisting mental health conditions. If detected, appropriate clinical management should be applied. Future studies should aim at optimizing dosing schedules to mitigate the adverse effects of rapid weight loss and further investigate GLP-1 agonists in possible STB prevention.