Bariatric surgery induces sustained weight loss and metabolic benefits via notable effects on the gut–brain axis that lead to alterations in the neuroendocrine regulation of appetite and glycaemia. However, in a subset of patients, bariatric surgery is associated with adverse effects on mental health, including increased risk of suicide or self-harm as well as the emergence of depression and substance use disorders. The contributing factors behind these adverse effects are not well understood. Accumulating evidence indicates that there are important links between gut-derived hormones, microbial and bile acid profiles, and disorders of mood and substance use, which warrant further exploration in the context of changes in gut–brain signalling after bariatric surgery. Understanding the basis of these adverse effects is essential in order to optimize the health and well-being of people undergoing treatment for obesity.

减肥手术通过对肠脑轴的显着影响导致食欲和血糖的神经内分泌调节发生改变，从而诱导持续的体重减轻和代谢益处。然而，在一部分患者中，减肥手术会对心理健康产生不利影响，包括增加自杀或自残的风险以及抑郁症和物质使用障碍的出现。这些不利影响背后的促成因素尚不清楚。越来越多的证据表明，肠源性激素、微生物和胆汁酸谱与情绪障碍和物质使用之间存在重要联系，这需要在减肥手术后肠-脑信号变化的背景下进一步探索。