Go to content

Repetition of intentional drug overdose: a population-based study


Context — Intentional overdose is a leading method of self-harm and suicide, and repeat attempts strongly predict eventual death by suicide.

Objectives — 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 — Design: Population-based cohort study.

Setting — Ontario, Canada, from 1 April 2002 to 31 March 2013.

Participants — All Ontario residents presenting to an emergency department after a first intentional overdose.

Main Outcome Measures — 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.

Discussion — 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.

Conclusion — Secondary prevention initiatives should be implemented for all individuals who present to the emergency department and survive intentional overdose.



Finkelstein Y, Macdonald EM, Hollands S, Sivilotti MLA, Hutson JR, Mamdani MM, Koren G, Juurlink DN; Canadian Drug Safety and Effectiveness Research Network (CDSERN). Clin Toxicol (Phila). 2016; 54(7):585-9. Epub 2016 May 12

View Source