The interpersonal theory of suicide proposes that non-suicidal self harm may act as a “gateway” to suicidal self harm and completed suicide, as people habituate to the pain and fear of harm through repeated exposure to self harm.42 43 In future work with this cohort we will examine whether those who had engaged only in non-suicidal self harm at 16 years went on to harm themselves with suicidal intent. Unfortunately we were unable to differentiate between self harm with suicidal intent and self harm without suicidal intent in the past year at age 21 years and were therefore unable to examine these outcomes separately in this study. We were also unable to investigate associations between self harm and future deaths from suicide; the incidence of suicide in 15-19 year olds is low, at fewer than 5 per 100 000 per year, and so much larger cohorts are required to investigate this outcome.
