ICU survivors are known to be at increased risk for psychiatric disorders, but it isn't known whether they are also at higher risk for suicide and self-harm. In a population-level cohort study, researchers investigated the incidence and risk factors associated with suicide and self-harm among adult survivors of critical illness. They then compared the associated risk with that of people who were hospitalized but not in the ICU.

A total of 423,060 consecutive ICU survivors and 3,081,111 consecutive non-ICU survivors were identified during the nine-year study period. During this time, the crude incidence (per 100,000 person-years) of suicide, self-harm, and the composite of suicide or self-harm among ICU survivors was 41.4, 327.9, and 361, respectively, compared with 16.8, 177.3, and 191.6 in non-ICU hospital survivors. After propensity score weighting, ICU survivors were found to have a higher risk of suicide, self-harm, and the composite of suicide or self-harm than non-ICU survivors.

Among ICU survivors, prognostic factors associated with suicide or self-harm included a history of mental health diagnoses (specifically, depression or anxiety, posttraumatic stress disorder, schizophrenia, and bipolar disorder) and the receipt of invasive mechanical ventilation or renal replacement therapy while in the ICU. Future research is needed to identify methods of reducing the risk of suicide and self-harm among ICU survivors, particularly in those who have certain prognostic factors, the authors conclude.

They caution that they can't rule out residual confounding because the study was observational. Also, external validation was lacking, and few data were available on protective factors.