Blood Biomarkers, Psychiatric History, and Mood Stabilizer Use Are Associated with Completed Suicide Among Psychiatric Inpatients Within 10 Years After Discharge: A Case-Control Study

OBJECTIVE: To investigate whether inflammatory and neurotrophic biomarkers, clinical variables, and psychiatric history are associated with completed suicide. METHODS: This case-control study included 24 inpatients with severe mental disorders (SMD) over 10 years, including 8 individuals who completed suicide and 16 matched ill-controls (IC). The study also included 16 healthy controls (HC). We analyzed serum inflammatory markers, BDNF levels, medication use, clinical psychiatric scores, and psychiatric history. RESULTS: Compared with ICs, suicide cases showed significantly higher serum levels of BDNF and IFN-γ and lower levels of IL-17. No significant differences were observed for TNF-α, IL-2, IL-4, IL-6, or IL-10. Suicide cases had higher numbers of prior psychiatric hospitalizations, previous suicide attempts, and greater use of mood stabilizers. Clinical psychiatric scale scores were not significantly associated with suicide during follow-up. CONCLUSION: Specific biological markers-particularly BDNF, IFN-γ, and IL-17-along with psychiatric history, especially prior suicide attempts and hospitalizations, appear to be important factors in completed suicide risk among SMD inpatients.