Selected groups of patients with bipolar & unipolar disorder have an increased mortality rate from suicide & natural causes of death. This population-based study of patients treated in the hospital documented increased standardized mortality ratios (SMRs) for suicide in patients with bipolar & unipolar disorder. The SMR for all natural causes of death was also increased, causing about half the excess deaths. For bipolar disorder, most excess deaths were from natural causes, whereas for unipolar disorders, most excess deaths were from unnatural causes. The SMR for suicide was especially high for younger patients during the 1st years after the 1st diagnosis. (39 refs.)