**2.9 Mental health issues**

Depression (19%) and binge eating disorder (17%) are the most common mental health conditions in the obese population.

Studies have shown improvement in mental health after bariatric surgery. A systematic review [71] reported a decrease in prevalence (8–74%) and severity (40–70%) of depression after bariatric surgery compared to before surgery.

Studies show contradictory reports about the influence of bariatric surgery on eating disorders. A retrospective study reported a durable decline in the loss of control of eating (5.4% post-RYGB vs. 16.2% before surgery), picking/nibbling (7.0% post-RYGB vs. 32.4% before surgery) and craving (19.4% 7 years post-RYGB vs. 33.6% before surgery) [72].

Another study [73] showed a decrease in binge eating disorder in the first two years from 6.1 to 1.3%, but it increased to 3.1% in 3 years.

A large retrospective study [49] reported a higher rate of suicides after RYGB (11.1 vs. 6.4 per 10,000 person-years, P = 0.04). Another large longitudinal cohort study [74] reported a 5-fold increase in deliberate self-harm (incidence rate ratio 4.7; 95% CI, 3.8–5.7). Suicide was reported in 9.6% of cases.

Moreover, studies have shown a high prevalence of alcohol and illicit drug abuse after bariatric surgery. King and Chen [75] observed higher incident alcohol use disorder (AUD) symptoms, substance use and illicit drug abuse after RYGB. Interestingly, the risk of incident AUD was twice higher with RYGB than LAGB.
