Evaluation of the association of bariatric surgery with subsequent depression

Bariatric surgery is helpful in enabling sustained weight loss, but effects on depression are unclear. Reductions in depression-related symptoms and increases in suicide rate have both been observed after bariatric surgery, but these observations are confounded by the presence of pre-existing depression. The goal of this study is to evaluate the effect of bariatric surgery on subsequent depression diagnosis. In this observational study, a prospective cohort study was simulated by evaluating depression risk based on diagnostic codes. An administrative database was utilized for this study, containing records and observations between 1 January 2008 through 29 February 2016 of enrolled patients in the United States. Individuals considered in this analysis were enrolled in a commercial health insurance program, observed for at least 6 months prior to surgery, and met the eligibility criteria for bariatric surgery. In all, 777,140 individuals were considered in total. Bariatric surgery was found to be significantly associated with subsequent depression relative to both non-surgery controls (HR = 1.31, 95% CI, 1.27–1.34, P < 2e–32) and non-bariatric abdominal surgery controls (HR = 2.15, 95% CI, 2.09–2.22, P < 2e–32). Patients with pre-surgical psychiatric screening had a reduced depression hazard ratio with respect to patients without (HR = 0.85, 95% CI, 0.81–0.89, P = 3.208e–12). Men were found to be more susceptible to post-bariatric surgery depression compared with women. Pre-surgical psychiatric evaluations reduced the magnitude of this effect. Relative to bariatric surgeries as a whole, vertical sleeve gastrectomy had a lower incidence of depression, while Roux-en Y Gastric Bypass and revision/removal surgeries had higher rates. In individuals without a history of depression, bariatric surgery is associated with subsequent diagnosis of depression. This study provides guidance for patients considering bariatric surgery and their clinicians in terms of evaluating potential risks and benefits of surgery.