Suicide, unintentional poisoning mortality, and nonfatal suicide attempts after involuntary psychiatric hospitalization

Little is known about the incidence of adverse outcomes after involuntary psychiatric hospitalization (IPH) in the United States. The objectives of this study were to use nonparametric competing risks analysis to estimate the incidences of suicide mortality, unintentional poisoning mortality, and nonfatal suicide attempt following discharge from IPH; to determine the most common methods of suicide death after IPH; and to use Cox proportional hazards modeling to investigate the association of sociodemographic and clinical factors with the risk of each outcome. People with a discharge from IPH in King County, Washington from 2016 – 2022 (N=22,019) were included. The cohort median age was 37 years (IQR: 27,53) with a median hospitalization length of 14 days (IQR: 7,25.5) for the most recent IPH. The 1-year rates of suicide and unintentional poisoning death were 598 per 100,000 person-years (95% CI: 497,714) and 931 per 100,000 person years (95% CI: 804,1073), while the average rates over 7 years were 185 per 100,000 person-years (95% CI: 157, 219) and 429 per 100,000 person-years (95% CI: 367,497). The 90-day rate of first nonfatal suicide attempt was 3407 per 100,000 person-years (95% CI: 2758,4177) and the average rate over 2.75 years was 880 per 100,000 person-years (95% CI: 742,1036). The most common method of suicide was suffocation or hanging (37.1%). A Danger-to-Self detainment order for the most recent IPH was associated with risk of both suicide and unintentional poisoning death. These results indicate a substantial risk of fatal suicide, nonfatal attempt, and unintentional poisoning death following discharge from IPH, with a critical period of risk in the first year. Further research into strategies for post-discharge care and mortality prevention after IPH is profoundly needed.