Bariatric surgery reduces mortality, but might have adverse effects on mental health. We assessed the risk of suicide and self-harm after bariatric surgery compared with non-surgical obesity treatment.
Suicide and non-fatal self-harm events retrieved from nationwide Swedish registers were examined in two cohorts. The non-randomised, prospective Swedish Obese Subjects (SOS) study compared bariatric surgery (n=2010; 1369 vertical-banded gastroplasty, 376 gastric banding, and 265 gastric bypass) with usual care (n=2037; recruitment 1987–2001). The second cohort consisted of individuals from the Scandinavian Obesity Surgery Registry (SOReg; n=20 256 patients who had gastric bypass) matched to individuals treated with intensive lifestyle modification (n=16 162; intervention 2006–13) on baseline BMI, age, sex, education level, diabetes, cardiovascular disease, history of self-harm, substance misuse, antidepressant use, anxiolytics use, and psychiatric health-care contacts.
During 68 528 person-years (median 18; IQR 14–21) in the SOS study, suicides or non-fatal self-harm events were higher in the surgery group (n=87) than in the control group (n=49; adjusted hazard ratio [aHR] 1.78, 95% CI 1.23–2.57; p=0.0021); of these events, nine and three were suicides, respectively (3.06, 0.79–11.88; p=0.11). In analyses by primary procedure type, increased risk of suicide or non-fatal self-harm was identified for gastric bypass (3.48, 1.65–7.31; p=0∙0010), gastric banding (2.43, 1.23–4.82; p=0.011), and vertical-banded gastroplasty (2.25, 1.37–3.71; p=0.0015) compared with controls. Out of nine deaths by suicide in the SOS surgery group, five occurred after gastric bypass (two primary and three converted procedures). During 149 582 person-years (median 3.9; IQR 2.8–5.2), more suicides or non-fatal self-harm events were reported in the SOReg gastric bypass group (n=341) than in the intensive lifestyle group (n=84; aHR 3.16, 2.46–4.06; p<0.0001); of these events, 33 and five were suicides, respectively (5.17, 1.86–14.37; p=0.0017). In SOS, substance misuse during follow-up was recorded in 48% (39/81) of patients treated with surgery and 28% (13/47) of controls with non-fatal self-harm events (p=0∙023). Correspondingly, substance misuse during follow-up was recorded in 51% (162/316) of participants in the SOReg gastric bypass group and 29% (23/80) of participants in the intensive lifestyle group with non-fatal self-harm events (p=0∙0003). The risk of suicide and self-harm was not associated with poor weight loss outcome.
Bariatric surgery was associated with suicide and non-fatal self-harm. However, the absolute risks were low and do not justify a general discouragement of bariatric surgery. The findings indicate a need for thorough preoperative psychiatric history assessment along with provision of information about increased risk of self-harm following surgery. Moreover, the findings call for postoperative surveillance with particular attention to mental health.
US National Institutes of Health and Swedish Research Council.