Abstract
OBJECTIVE: To estimate the cumulative incidence of self-reported suicide-related thoughts (SRTs) and suicide attempts (SAs) in males and females from 11 to 25 years of age in Canada. METHODS: A cohort study was conducted by linking cycles 2 to 8 from the National Longitudinal Survey of Children and Youth, a representative survey of Canadians aged 11 to 25 years conducted from 1996 to 2009. The 11- to 25-year cumulative incidence of self-reported SRTs and SAs (with suicidal intent) was estimated in males and females using a novel application of a counting process approach to account for discontinuous risk intervals between survey cycles. RESULTS: The risk of SRTs was 29% (95% confidence interval [CI], 26% to 31%) in females and 19% (95% CI, 16% to 23%) in males. The risk of SAs was 16% (95% CI, 14% to 19%) in females and 7% (95% CI, 6% to 8%) in males. Over 70% of SRTs and SAs first occur between 11 and 16 years of age and 30% between 11 and 13 years of age, respectively. CONCLUSIONS: The risk of SRTs and SAs is high in young Canadians, with most events first occurring in early to mid-adolescence and possibly earlier. Females are at a higher risk compared to males. This research underscores the need for better longitudinal surveillance of SRTs and SAs in the population. A counting process framework could be useful for future research using existing longitudinal surveys suffering from design limitations relating to gaps in respondent follow-up. Furthermore, these findings have implications for younger SRT and SA risk management by clinicians and earlier implementation of suicide prevention programs.