Objective: To assess the association between suicide attempts among females before 20 years of age and future risk of substance use disorders.
Design, Setting, and Participants: In this longitudinal cohort study, females aged 8 to 19 years (hereafter referred to as youths) who attempted suicide were matched with female youths with no attempt between April 1, 1989, and March 31, 2019, in Quebec, Canada. The cohort was followed up for 31 years, for a total of 2 409 396 person-years, to identify subsequent substance use disorders.
Exposures: Confirmed suicide attempts among females 8 to 19 years of age.
Main Outcomes and Measures: The main outcome measure was hospitalization for a substance use disorder later in life. Hazard ratios (HRs) and 95% CIs for the association of suicide attempt with substance use disorders were estimated using Cox proportional hazards regression models adjusted for baseline age, mental illness, resource-limited socioeconomic status, and year at start of follow-up.
Results: Among 122 234 female youths (mean [SD] age, 15.6 [1.9] years), 5840 (4.8%) attempted suicide and 4341 (3.6%) developed a substance use disorder. Compared with the 116 394 matched female youths who did not attempt suicide (95.2%), those who attempted suicide had a greater risk of hospitalization for any substance use disorder during the follow-up period (HR, 6.03; 95% CI, 5.39-6.77), especially sedative or hypnotic use disorders (HR, 32.24; 95% CI, 23.29-44.64). Suicide attempt was associated with the development of sedative or hypnotic use disorders up to 5 years (HR, 66.69; 95% CI, 34.72-128.09), although risks remained elevated up to 3 decades later for all substances. Compared with those without suicide attempt, female youths with 3 or more suicide attempts had 21.20 (95% CI, 13.53-32.90) times the risk of substance use disorders, whereas female youths with 1 attempt had 5.70 (95% CI, 5.08-6.41) times the risk of these disorders.
Conclusions and Relevance: In this cohort study, female youths who attempted suicide had increased risk of subsequent substance use disorders compared with female youths who did not attempt suicide. These findings suggest that closer management and prevention of substance use among female youths who attempt suicide may be beneficial.