Impact of psychiatric medication on suicide reattempt risk in patients with depression: A retrospective cohort study using national health insurance data in Korea.

BACKGROUND: This post-hoc analysis examined the effect of sustained psychiatric medication on suicide reattempt risk among Korean patients with depression following an initial attempt. METHODS: Using the Korean Health Insurance Review and Assessment Service (HIRA) database, we identified adults aged 18 years and older diagnosed with depressive disorder who attempted suicide in 2014 (N = 4925; mean age 47.4 ± 17.3 years, range 19-96). Sustained psychiatric medication was defined as receiving antidepressant or antipsychotic treatment for ≥75% of the six months after the index attempt. Stabilized inverse-probability-of-treatment weighting (IPTW) based on propensity scores addressed baseline imbalances. Logistic regression assessed one-year reattempt risk; survival analyses examined long-term risk over up to seven years (from index through August 31, 2020; median follow-up 5.9 years, maximum 6.7 years). Exploratory subgroup analyses compared patients <65 and ≥ 65 years. RESULTS: After IPTW, baseline characteristics were balanced. The one-year reattempt rate was 5.3% with medication versus 7.9% without (OR:0.65, 95% CI:0.504-0.846, P = 0.001). Survival analyses over the seven-year follow-up showed no significant long-term difference (IPTW-adjusted log-rank P = 0.886). The protective effect was evident only in patients <65 years (OR:0.621, 95% CI:0.471-0.822, P < 0.001), with no significant effect in those ≥65 years. CONCLUSIONS: Sustained psychiatric medication after a suicide attempt reduces one-year reattempt risk in patients with depression, in particular in those aged under 65 years. The benefit of initial treatment did not persist over seven years, suggesting that the effect of continued treatment beyond six months warrants future investigation.