Excess Mortality in Bipolar and Unipolar Disorder in Sweden

Abstract

Selected groups of patients with bipolar and unipolar disorder have an increased mortality rate from suicide and natural causes of death. However, there has been no population-based study of mortality of patients followed up from the onset of the illness. All patients with a hospital diagnosis of bipolar (n = 15 386) or unipolar (n = 39 182) disorder in Sweden from 1973 to 1995 were identified from the inpatient register and linked with the national cause-of-death register to determine the date and cause of death. Overall and cause-specific standardized mortality ratios (SMRs) and numbers of excess deaths were calculated by 5-year age classes and 5-year calendar periods. The SMRs for suicide were 15.0 for males and 22.4 for females with bipolar disorder, and 20.9 and 27.0, respectively, for unipolar disorder. For all natural causes of death, SMRs were 1.9 for males and 2.1 for females with bipolar disorder, and 1.5 and 1.6, respectively, for unipolar disorder. For bipolar disorder, most excess deaths were from natural causes, whereas for unipolar disorder, most excess deaths were from unnatural causes. The SMR for suicide was especially high for younger patients during the first years after the first diagnosis. Increasing SMR for suicide during the period of study was found for female patients with unipolar disorder. This population-based study of patients treated in the hospital documented increased SMRs for suicide in patients with bipolar and unipolar disorder. The SMR for all natural causes of death was also increased, causing about half the excess deaths.