Non-suicidal self-injury and suicide attempts in a New Zealand birth cohort

Background: Non-suicidal self-injury (NSSI) and suicide attempts are related, but distinct behaviors. The primary aim of the current study was to identify factors that distinguish those with different lifetime histories of selfinjury. A secondary aim was to test whether lifetime history of self-injury at age 26 predicted current suicide ideation at age 32. Methods: Participants were 26 year olds from a large birth cohort with a lifetime history of no self-injury (n = 466), a lifetime history of NSSI (n = 191), or a lifetime history of NSSI and a suicide attempt (NSSI+ SA; n = 52). They were compared on a history of psychiatric disorders, 12-month suicide ideation, lifetime history of childhood sexual abuse, and lifetime exposure to suicide. Results: An anxiety disorder, a substance dependence disorder, suicide ideation, and a history of childhood sexual abuse distinguished the NSSI+ SA and NSSI only groups. Longitudinal results demonstrated that a history of NSSI predicted future suicide ideation after adjusting for other selected risk factors. Limitations: The majority of analyses are cross-sectional which limits inferences about causality. The retrospective self-report for lifetime behavior could be subject to reporting biases. Conclusions: Adults with a history of NSSI and adults with a history of NSSI and a suicide attempt are clinically distinct groups that are both at risk of future suicide ideation. Identifying and treating NSSI could be a key preventive factor in reducing subsequent suicide risk.