Immediate improvement in anxiety and sleep quality with delayed depression response after bariatric surgery in a longitudinal cohort study

Obesity demonstrates bidirectional associations with anxiety, depression and sleep quality. Although bariatric surgery effectively alleviates obesity-related mental health issues, the mechanisms and temporal dynamics of mental symptom improvements remain unclear. This longitudinal study aims to explore the time points at which mental health and sleep quality change after bariatric surgery in overweight/obese patients, and explore correlation between anxiety, depression and sleep quality. Seventy-eight overweight/obese patients (OW/OB) who underwent Laparoscopic sleeve gastrectomy at the Bariatric Center of Shanghai Sixth People's Hospital were included by cohort. Sixty-five healthy controls (HC) were matched by age and sex. Patients received Chinese versions of the Beck Depression Inventory II (BDI), Beck Anxiety Inventory (BAI), and Pittsburgh Sleep Quality Index (PSQI) completed during monthly follow-up surveys after surgery. Before surgery, the OW/OB group had significantly worse anxiety, depression, and sleep problems than HC (all p < 0.001). After surgery, BAI and PSQI scores decreased significantly at all time points, and BDI scores began to decrease at 1 year postoperatively compared with baseline (all p < 0.05). There was a stable positive correlation between preoperative body mass index, BAI, BDI, and PSQI scores, which broke down in the postoperative period. Bariatric surgery improved anxiety symptoms and sleep quality in overweight or obese patients, while depressive symptoms showed delayed but statistically significant improvements at later follow-up points. Stable associations between anxiety, depression, and sleep quality in overweight or obese patients may require multiple interventions.