The Association Between Bariatric Surgery and Psychiatric Disorders: a National Cohort Study

Purpose Previous studies have shown that bariatric surgery reduces the risk of cardiovascular outcomes. Less is known about the effects of bariatric surgery on psychiatric disorders. This cohort study compared the differential risk of psychiatric disorders between those who did and did not undergo bariatric surgery, from before until after the surgery. Materials and Methods We used PearlDiver-Mariner, a national all-payor claims database. Patients were followed for 1 year before and after the index date and a difference-in-differences (DiD) study design was executed. Results We included 56,661 bariatric surgery patients matched to 56,661 individuals with obesity. Among bariatric surgery patients, the risk of psychiatric was 18% 1 year before and increased to 70% 1 year after surgery. Among individuals with obesity, the risk of psychiatric disorders also increased from 1 year before to 1 year after, but by less (21% versus 46%). DiD analysis suggested that bariatric surgery was associated with a 27 percentage point differential increase in the risk of psychiatric disorders across all patients, representing a 135% relative increase. Results using 3 years as the pre- and post-periods lead to similar inferences. Conclusion Preexisting psychiatric disorders are similarly prevalent among bariatric surgery patients and individuals with obesity. The prevalence of psychiatric disorders increased over time for both groups, but to a larger extent among bariatric surgery patients. Adequate treatment for psychiatric disorders and appropriate implementation of behavioral health interventions may be needed to reduce the burden of psychiatric disorders following bariatric surgery. Graphical abstract