Criminality and suicide: a longitudinal Swedish cohort study

OBJECTIVES: This study aimed to investigate whether violent and non-violent offending were related to elevated risk of suicide. We also investigated whether the risk was higher among those with repeated offences and how experiences of substance misuse and suicide attempt modified the relationship. DESIGN: A nationwide prospective cohort study. SETTING: A register study of 48 834 conscripted men in 1969/1970 in Sweden followed up during a 35-year period in official registers. PARTICIPANTS: A birth cohort of 48 834 men who were mandatory conscripted for military service in 1969/70 at the age of 18–20 years. Possible confounders were retrieved from psychological assessments at conscription and the cohort was linked to mortality and hospitalisation and crime records from 1970 onwards. Estimates of suicide risks were calculated as HR with 95% CIs using Cox proportional regression analyses with adjustment for potential confounding by family, psychological and behavioural factors including substance use and psychiatric disorders. RESULTS: Of the total cohort, 2671 (5.5%) persons died during the follow-up period. Of these, 615 (23%) persons died due to suicide. Non-violent criminality was evident for 29% and violent criminality for 4.7% of all the participants. In the crude model, the violent offenders had nearly five times higher risk (HR=4.69, 3.56 to 6.19) to die from suicide and non-violent criminals had about two times higher risk (HR=2.08, 1.72 to 2.52). In the fully adjusted model, the HRs were still significant for suicide in the non-violent group. CONCLUSIONS: Experiences of violent or non-violent criminality were associated with increased risk of suicide. Comorbidity with alcohol and substance use and psychiatric disorders modified the risk, but the suicide risk remained significantly elevated for non-violent criminals. It is crucial to identify offenders and especially repeated offenders who also suffer from alcohol or substance misuse and psychiatric illness in clinical settings in order to prevent suicide.