title: Long-term outcomes following self-poisoning in adolescents: a population-based cohort study.
abstract: BACKGROUND
  Suicide is the third most common cause of death among adolescents worldwide, and poisoning is the leading method of attempted suicide. Unlike more violent methods, survival after self-poisoning is common, providing an opportunity for secondary prevention. We determined the risk and time course of completed suicide after adolescent self-poisoning, and explored potential risk factors.
  
  
  METHODS
  We did a population-based cohort study using multiple linked health-care databases in Ontario, Canada, from Jan 1, 2001, to Dec 31, 2012. We identified all adolescents aged 10-19 years presenting to hospital after a first self-poisoning episode. Each was matched with 50 population-based reference individuals with no such history, matching on age, sex, and year of cohort entry. The primary outcome was the risk of suicide after a first self-poisoning episode. Secondary analyses explored factors associated with suicide and self-poisoning repetition.
  
  
  RESULTS
  We identified 20,471 adolescents discharged from hospital after a first self-poisoning episode and 1,023,487 matched reference individuals. Over a median follow-up of 7·2 years (IQR 4·2-9·7), 248 (1%) adolescents discharged after self-poisoning died, 126 (51%) of whom died by suicide. The risk of suicide at 1 year after self-poisoning was greatly increased relative to reference individuals (hazard ratio [HR] 32·1, 95% CI 23·6-43·6), corresponding to a suicide rate of 89·6 (95% CI 75·2-106·7) per 100,000 person-years over the course of follow-up. The median time from hospital discharge to suicide was 3·0 years (IQR 1·1-5·3). Factors associated with suicide included recurrent self-poisoning (adjusted HR 3·5, 95% CI 2·4-5·0), male sex (2·5, 1·8-3·6) and psychiatric care in the preceding year (1·7, 1·1-2·5). Adolescents admitted to hospital for self-poisoning were also more likely to die from accidents (5·2, 4·1-6·6) and from all causes (3·9, 2·8-5·4) during follow-up.
  
  
  CONCLUSIONS
  Self-poisoning in adolescence is a strong predictor of suicide and premature death in the ensuing decade, and identifies a high-risk group for targeted secondary prevention. Suicide risk is increased for many years after the index hospital admission, emphasising the importance of sustained prevention efforts.
  
  
  BACKGROUND
  The Canadian Drug Safety and Effectiveness Research Network, Ontario Ministry of Health and Long-Term Care, Paediatric Consultants Partnership.
authors.affiliation: Divisions of Emergency Medicine, Hospital for Sick Children, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Clinical Pharmacology and Toxicology, Hospital for Sick Children, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Child Health Evaluative Sciences, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada. Electronic address: yaron.finkelstein@sickkids.ca.
authors.forename: Yaron
authors.initials: Y
authors.lastname: Finkelstein
authors.affiliation: The Institute for Clinical Evaluative Sciences, Toronto, ON, Canada.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Macdonald
authors.affiliation: The Institute for Clinical Evaluative Sciences, Toronto, ON, Canada.
authors.forename: Simon
authors.initials: S
authors.lastname: Hollands
authors.affiliation: Clinical Pharmacology and Toxicology, Hospital for Sick Children, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
authors.forename: Janine R
authors.initials: JR
authors.lastname: Hutson
authors.affiliation: Departments of Emergency Medicine and Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
authors.forename: Marco L A
authors.initials: ML
authors.lastname: Sivilotti
authors.affiliation: The Institute for Clinical Evaluative Sciences, Toronto, ON, Canada; Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St Michael's Hospital, Toronto, ON, Canada; Dalla Lana School of Public Health, University of Toronto, Institute of Health Policy, Management, and Evaluation, ON, Canada; Departments of Medicine and Peadiatrics, University of Toronto, ON, Canada; Leslie Dan Faculty of Pharmacy, University of Toronto, ON, Canada.
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Mamdani
authors.affiliation: Clinical Pharmacology and Toxicology, Hospital for Sick Children, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Child Health Evaluative Sciences, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Gideon
authors.initials: G
authors.lastname: Koren
authors.affiliation: Clinical Pharmacology and Toxicology, Hospital for Sick Children, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; The Institute for Clinical Evaluative Sciences, Toronto, ON, Canada; Sunnybrook Research Institute, Sunnybrook Hospital, Toronto, ON, Canada; Departments of Medicine and Peadiatrics, University of Toronto, ON, Canada.
authors.forename: David N
authors.initials: DN
authors.lastname: Juurlink
mesh_terms: D000293:Adolescent; D002648:Child; D003863:Depression / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D009864:Ontario / Q000453:epidemiology; D010351:Patient Discharge / Q000706:statistics & numerical data; D011041:Poisoning / Q000453:epidemiology* / Q000523:psychology; D012307:Risk Factors; D016728:Self-Injurious Behavior / Q000453:epidemiology; D013405:Suicide / Q000523:psychology / Q000706:statistics & numerical data; D013406:Suicide, Attempted / Q000706:statistics & numerical data*