title: Risk of psychiatric disorders, self-harm behaviour and service use associated with bariatric surgery.
abstract: OBJECTIVE
  To investigate psychiatric outcomes after bariatric surgery, including suicide, self-harm, psychiatric service use and substance misuse.
  
  
  METHODS
  Retrospective study on a Danish nationwide register-based cohort of 22 451 patients followed for 1 029 736 person-years. Data were analysed utilizing single- and multi-event Cox regression with non-operated controls with obesity and mirror-image analyses with the operated patient serving as their own controls.
  
  
  RESULTS
  We showed an increased ratio of self-harm (hazard ratio [HR] 3.23, P < 0.001; incidence rate ratio [IRR] 1.71, P < 0.001), psychiatric service use (admissions IRR 1.52, P < 0.001; emergency room visits IRR 1.70, P < 0.001), psychiatric diagnosis (organic psychiatric disorders HR 1.78, P < 0.001; substance use HR 2.06, P < 0.001; mood disorders HR 2.66, P < 0.001; neurotic, stress-related and somatoform disorders HR 2.48, P < 0.001; behavioural syndromes HR 3.15, P < 0.001; disorders of personality HR 2.68, P < 0.001; behavioural and emotional disorders HR 6.43, P < 0.001), as well as substance misuse utilizing Cox regression as well as mirror-image analyses, as compared to non-operated. We did not find an increased suicide rate (HR 1.35, P = 0.658) among operated as compared to non-operated.
  
  
  CONCLUSIONS
  Our study shows that undergoing bariatric surgery is associated with increases in self-harm, psychiatric service use and occurrence of mental disorders.
authors.affiliation: Unit for Psychiatric Research, Department of Psychiatry, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Z
authors.initials: Z
authors.lastname: Kovacs
authors.affiliation: Unit for Psychiatric Research, Department of Psychiatry, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: J B
authors.initials: JB
authors.lastname: Valentin
authors.affiliation: Unit for Psychiatric Research, Department of Psychiatry, Aalborg University Hospital, Aalborg, Denmark.|Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: R E
authors.initials: RE
authors.lastname: Nielsen
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000009:adverse effects*; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology*; D008605:Mental Health Services / Q000706:statistics & numerical data*; D008875:Middle Aged; D012189:Retrospective Studies; D016728:Self-Injurious Behavior / Q000453:epidemiology*; D013405:Suicide / Q000706:statistics & numerical data*
keywords: behaviour; health service; self-harm; substance use disorder