Psychiatric and Cognitive Functioning After Metabolic and Bariatric Surgery: A Systematic Review and Meta-Analysis.

Abstract

To systematically review and meta-analyze psychiatric and cognitive outcomes following metabolic and bariatric surgery (MBS). [Correction added on 1 July 2025, after first online publication: The objective statement has been updated for clarity.] METHODS: Six databases were searched. Randomized controlled trials (RCTs) and nonrandomized studies (NRS) of people with obesity comparing MBS with any nonsurgical intervention or control condition were included. Main outcomes included symptoms of depression, anxiety, and non-normative eating, substance use disorder diagnosis, suicide death, and cognitive performance in attention, memory, and executive function. Evidence certainty was assessed with GRADE. Heterogeneity was explored with subgroup analyses of ≤ 2 years vs. > 2 years post-intervention. There were 79 studies (75 NRS and 4 RCTs) found, including 732,149 people with obesity who underwent MBS, and 7,670,770 who did not. Among RCTs, MBS may improve depressive symptoms (standardized mean difference [SMD] = -0.40, 95% CI -1.04, 0.24; very low certainty). Among NRS, there was low to very low certainty that MBS may improve depressive (SMD = 0.56, 95% CI -0.87, -0.26), anxiety (SMD = -0.60, 95% CI -1.00, -0.19), and non-normative eating symptoms (SMD = -0.75, 95% CI -0.97, -0.53) and cognitive performance in attention (SMD = -0.72, 95% CI -1.61, 0.17), but not executive function or memory. MBS may slightly increase suicide deaths (1/1000 more people, 95% CI 0 fewer to 3 more; very low certainty) and substance use disorders (4/100 more, 95% CI from 1 to 9 more; low certainty) > 2-years post-surgery. Compared to nonsurgical conditions, MBS may improve depression, anxiety, non-normative eating, and attention, but slightly increase suicides and substance use disorders. There was low to very low certainty in most outcomes, therefore additionalhigh-quality studies are needed to strengthen the evidence base.