Suicide Following Deliberate Self-Harm

TLDR

The study aimed to identify risk factors for repeat self‑harm and suicide within a year among adults who had deliberate self‑harm. A national Medicaid cohort of 61,297 adults with clinically diagnosed deliberate self‑harm was followed for up to one year, with repeat self‑harm and suicide rates calculated per person‑year and hazard ratios estimated using Cox proportional hazards models. In the first year after nonfatal self‑harm, repeat self‑harm occurred at 263.2 per 1,000 person‑years and suicide at 439.1 per 100,000 person‑years—37.2 times higher than a matched general population—and the risk of suicide was markedly greater after violent methods, especially firearms, with a hazard ratio of 15.86 and a 17.5‑fold increase in the first 30 days.

Abstract

Objective: The authors sought to identify risk factors for repeat self-harm and completed suicide over the following year among adults with deliberate self-harm. Method: A national cohort of Medicaid-financed adults clinically diagnosed with deliberate self-harm (N=61,297) was followed for up to 1 year. Repeat self-harm per 1,000 person-years and suicide rates per 100,000 person-years (based on cause of death information from the National Death Index) were determined. Hazard ratios of repeat self-harm and suicide were estimated by Cox proportional hazard models. Results: During the 12 months after nonfatal self-harm, the rate of repeat self-harm was 263.2 per 1,000 person-years and the rate of completed suicide was 439.1 per 100,000 person-years, or 37.2 times higher than in a matched general population cohort. The hazard of suicide was higher after initial self-harm events involving violent as compared with nonviolent methods (hazard ratio=7.5, 95% CI=5.5–10.1), especially firearms (hazard ratio=15.86, 95% CI=10.7–23.4; computed with poisoning as reference), and to a lesser extent after events of patients who had recently received outpatient mental health care (hazard ratio=1.6, 95% CI=1.2–2.0). Compared with self-harm patients using nonviolent methods, those who used violent methods were at significantly increased risk of suicide during the first 30 days after the initial event (hazard ratio=17.5, 95% CI=11.2–27.3), but not during the following 335 days. Conclusions: Adults treated for deliberate self-harm frequently repeat self-harm in the following year. Patients who use a violent method for their initial self-harm, especially firearms, have an exceptionally high risk of suicide, particularly right after the initial event, which highlights the importance of careful assessment and close follow-up of this group.