The relationship between NSSI and suicide is complex. Although NSSI is not a suicidal behavior itself, it is a reliable predictor of later suicidal thoughts, plans, and attempts (Kiekens et al., 2018, Ribeiro et al., 2016).

So, why is this the case?

There are lots of factors that contribute to the relationship between NSSI and suicidal behaviours. A recent review by Griep and MacKinnon (2020) found that past-year NSSI frequency and depressive symptoms increase an individual's risk of attempting suicide. There were mixed findings regarding age and sex differences.

References

• Kiekens, G., Hasking, P., Boyes, M., Claes, L., Mortier, P., Auerbach, R. P., Cuijpers, P., Demyttenaere, K., Greene, J. G., Kessler, R. C., Myin-Germeys, I., Nock, M. K., & Bruffaerts, R. (2018). The associations between non-suicidal self-injury and first onset suicidal thoughts and behaviors. Journal of Affective Disorders, 239, 171-179. https://doi.org/10.1016/j.jad.2018.06.033

• Griep, S. K., & MacKinnon, D. F. (2020). Does nonsuicidal self-injury predict later suicidal attempts? A review of studies. Archives of Suicide Research, 26, 428-446. https://doi.org/10.1080/13811118.2020.1822244

• Ribeiro, J. D., Franklin, J. C., Fox, K. R., Bentley, K. H., Kleiman, E. M., Chang, B. P., & Nock, M. K. (2015). Self-injurious thoughts and behaviors as risk factors for future suicide ideation, attempts, and death: A meta-analysis of longitudinal studies. Psychological Medicine, 46, 225-236. https://doi.org/10.1017/S0033291715001804