Overlapping patterns of suicide attempts and non-suicidal self-injuries in adults: A prospective clinical cohort study

Objective: An overlap of non-suicidal self-injuries (NSSIs) and suicide attempts (SAs) is observed in young cohorts, but there are few robust prospective studies for adults. We compared 1-year outcomes in adults with different self-harm patterns: NSSI only, NSSI + SA, and SA only. Methods: 793 patients (67% women) consecutively presenting with NSSI (17%) or SA (83%) at 3 Swedish hospitals took part in face-to-face interviews. Past and current self-harm was characterized by the Columbia-Suicide Severity Rating Scale. Clinical records and national register data were employed to determine 1-year outcomes. Results: At inclusion, over half of the participants had engaged in both NSSI and SA; 41% had SA only and 5%, NSSI only. During follow-up, non-fatal SAs were observed in approximately one-third of the total group (n = 269). Suicides occurred in 2% of those with NSSI + SA; the same proportion was seen in the SA only group. No suicides were observed in those with NSSI only. In a multiple logistic regression analysis, the NSSI + SA pattern was associated with a more than 3-fold risk of subsequent fatal/non-fatal suicidal behavior compared to “pure” NSSI; risk was not elevated in those with “pure” SA. Neither sex nor age group predicted subsequent suicidal behavior. Conclusions: Switching between behaviors with and without suicidal intent was common in this adult clinical cohort. Risk of subsequent suicidal behavior was tripled in the combined group. Clinicians who assess adults with NSSI must evaluate not only current but also previous episodes when assessing future risk of suicidal behavior.