Post-discharge suicides of inpatients with bipolar disorder in Finland

Objectives: Suicide risk in psychiatric inpatients is known to be remarkably high after discharge. However, temporal patterns and risk factors among patients with bipolar disorder remain obscure. We investigated post-discharge temporal patterns of hazard and risk factors by type of illness phase among patients with bipolar disorder. Methods: Based on national registers, all discharges of patients with bipolar disorder from a psychiatric ward in Finland in 1987-2003 (n = 52,747) were identified, and each patient was followed up to post-index discharge or to suicide (n = 466). For discharges occurring in 1995-2003 (n = 35,946), factors modifying hazard of suicide during the first 120 days (n = 129) were investigated. Results: The temporal pattern of suicide risk depended on the type of illness phase, being highest but steeply declining after discharge with depression; less high and declining in mixed states; lower and relatively stable after mania. In Cox models, for post-discharge suicides (n = 65) after hospitalizations for bipolar depression (n = 9,635), the hazard ratio was 8.05 (p = 0.001) after hospitalization with a suicide attempt and 3.63 (p < 0.001) for male patients, but 0.186 (p = 0.001) for patients taking lithium. Suicides after mania (n = 28) or mixed episodes (n = 20) were predicted by male sex and preceding suicide attempts, respectively. Conclusions: Among inpatients with bipolar disorder, suicide risk is high and related strongly to the time elapsed from discharge after hospitalizations for depressive episodes, and less strongly after hospitalizations for mixed episodes. Intra-episodic suicide attempts and male sex powerfully predict suicide risk. Lower suicide rate after hospitalizations for depression among patients prescribed lithium is consistent with a preventive effect.