title: Repetition of intentional drug overdose: a population-based study.
abstract: BACKGROUND
  Intentional overdose is a leading method of self-harm and suicide, and repeat attempts strongly predict eventual death by suicide.
  
  
  OBJECTIVE
  To determine the risk of recurrence after a first intentional overdose. Secondary objectives included characterization of the temporal course and potential predictors of repeat overdose, a strong risk factor for death from suicide.
  
  
  METHODS
  
  
  
  METHODS
  Population-based cohort study.
  
  
  METHODS
  Ontario, Canada, from 1 April 2002 to 31 March 2013.
  
  
  METHODS
  All Ontario residents presenting to an emergency department after a first intentional overdose.
  
  
  METHODS
  The incidence and timing of recurrent overdose.
  
  
  RESULTS
  We followed 81,675 patients discharged from hospital after a first intentional overdose. Overall, 13,903 (17.0%) returned with a repeat overdose after a median interval of 288 (inter-quartile range: 62 to 834) days. Of these, 4493 (5.5%) had multiple repeat episodes. Factors associated with repeat self-poisoning included psychiatric care in the preceding year (adjusted hazard ratio [aHR] 1.55; 95% confidence interval [CI] 1.50 to 1.61), alcohol dependence (aHR 1.41; 95% CI 1.35 to 1.46) and documented depression (aHR 1.39; 95% CI 1.34 to 1.44). Female sex, rural residence, lower socioeconomic status, ingestion of psychoactive drugs and younger age were also weakly associated with repeat overdose.
  
  
  CONCLUSIONS
  Hospital presentation for repetition of intentional overdose is common, with recurrent episodes often far removed from the first. While several factors predict overdose repetition, none is particularly strong.
  
  
  CONCLUSIONS
  Secondary prevention initiatives should be implemented for all individuals who present to the emergency department and survive intentional overdose.
authors.affiliation: a Division of Emergency Medicine, Hospital for Sick Children, Faculty of Medicine , University of Toronto , Toronto , Canada ;|b Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, Faculty of Medicine , University of Toronto , Toronto , Canada ;|c Child Health Evaluative Sciences, Research Institute , the Hospital for Sick Children , Toronto , Canada ;
authors.forename: Yaron
authors.initials: Y
authors.lastname: Finkelstein
authors.affiliation: d The Institute for Clinical Evaluative Sciences , Toronto , Canada ;
authors.forename: Erin M
authors.initials: EM
authors.lastname: Macdonald
authors.affiliation: d The Institute for Clinical Evaluative Sciences , Toronto , Canada ;
authors.forename: Simon
authors.initials: S
authors.lastname: Hollands
authors.affiliation: e Department of Emergency Medicine , Queen's University , Kingston , Canada ;|f Department of Biomedical and Molecular Sciences , Queen's University , Kingston , Canada ;
authors.forename: Marco L A
authors.initials: ML
authors.lastname: Sivilotti
authors.affiliation: b Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, Faculty of Medicine , University of Toronto , Toronto , Canada ;
authors.forename: Janine R
authors.initials: JR
authors.lastname: Hutson
authors.affiliation: g Applied Health Research Centre (AHRC) , Li Ka Shing Knowledge Institute of St. Michael's Hospital , Toronto , Canada ;|h Dalla Lana School of Public Health , University of Toronto , Canada ;
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Mamdani
authors.affiliation: b Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, Faculty of Medicine , University of Toronto , Toronto , Canada ;|c Child Health Evaluative Sciences, Research Institute , the Hospital for Sick Children , Toronto , Canada ;
authors.forename: Gideon
authors.initials: G
authors.lastname: Koren
authors.affiliation: d The Institute for Clinical Evaluative Sciences , Toronto , Canada ;|i Sunnybrook Hospital , Sunnybrook Research Institute , Toronto , Canada ;|j Departments of Medicine, Pediatrics and Health Policy, Management and Evaluation , University of Toronto , Canada.
authors.forename: David N
authors.initials: DN
authors.lastname: Juurlink
mesh_terms: D000328:Adult; D000368:Aged; D002170:Canada; D015331:Cohort Studies; D062787:Drug Overdose / Q000453:epidemiology*; D004636:Emergency Service, Hospital; D005260:Female; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012008:Recurrence; D012307:Risk Factors; D016728:Self-Injurious Behavior / Q000453:epidemiology*; D013406:Suicide, Attempted / Q000517:prevention & control; D055815:Young Adult
keywords: Recidivism; self-poisoning; suicide