Impact of antidepressant use on post-operative weight loss following bariatric surgery

Background: Antidepressant medication can be associated with weight gain. Consideration should be given to the specific agent prescribed to optimize bariatric surgery outcomes. Aim: The aim of this study is to investigate if patients treated with antidepressants stratified by risk of weight gain are associated with less weight loss at 1 year postbariatric surgery. Method: A single centre, retrospective analysis of all patients who underwent bariatric surgery between July 2018 and 2021 within St Vincent's University Hospital group. The exposure was antidepressant use, stratified for risk of weight gain, and the control group was patients who underwent surgery but no antidepressant use. The primary outcome was % TWL (total weight loss) at 6 weeks, 6 months and 12 months post-surgery. Multivariate linear regression analysis was used to estimate the impact of antidepressant treatment on post-surgery weight loss at 12 months using the variables of age, gender and pre-operative BMI. Results: Of the total cohort (n = 315), 70 patients (22.2%) were taking antidepressants. At 12 months, post-operatively patients taking medium risk for weight gain antidepressants had significantly less mean %TWL compared to those not taking antidepressants (p = 0.015). Overall, taking any antidepressant was not found to be a significant predictor of %TWL at 12 months after surgery (β = - 2.590, p = 0.0836). Conclusion: Many patients undergoing bariatric surgery have concurrent psychiatric conditions. Given the complex relationship between bariatric surgery and mental health, psychotropic medications may be best managed by a specialist in the field such as a bariatric psychiatrist in order to optimize patient outcomes.