Mortality in schizophrenia and affective disorder

Abstract

Patients with psychiatric disorders such as schizophrenia, bipolar disorder and unipolar disorder have a considerably increased mortality compared to the population. To reduce this increased mortality is a major task for clinical psychiatry, and the aim of this study is to improve the knowledge about the increased mortality in order to reduce its effects for the patients. The studies in this thesis are based upon register linkages. Information about diagnosis and time of admission and discharge from the Patient register has been linked with information about cause and time of death from the Cause-of-death register, and information about first-degree relatives from the Second-generation register.

First admissions with schizophrenia in Stockholm County during 1978 to 1994 were reduced by 1.3% yearly for males and 1.9% for females, while first admissions with either schizophrenia or paranoid psychosis were unchanged for both sexes, indicating that the reduction of first schizophrenia admissions may be an effect of diagnostic changes during the study period.

For schizophrenics in Stockholm County followed-up from the first diagnosis, standardized mortality ratios (SMR:s) for all causes of death were increased to 2.8 for males and 2.4 for females. SMR was most increased in suicide, with 15.7 for males and 19.7 for females, and in unspecified violence, with 11.7 for males and 9.9 for females. SMR:s for suicide were particularly increased for young patients during the first year after the first admission. More excess deaths were caused by natural (somatic) than by unnatural causes of death, although the specific causes of death that caused most extra deaths were suicide in males and cardiovascular disease in females.

Time trends in SMR for all causes of death during 1976 to 1995, for patients in Stockholm County diagnosed with schizophrenia for the first time, increased 1.7 times for males and 1.3 times for females. Cardiovascular death increased 4.7 times for males and 2.7 times for females, while all unnatural causes of death increased 1.8 times for males and suicide increased 1.9 times for females. The increase in mortality may be an effect of the concomitant reduction with 64% of days in hospital for schizophrenia.

SMR:s for all patients with a hospital diagnosis of bipolar or unipolar disorder in Sweden for all causes of death were 2.5 for males and 2.7 for females in bipolar disorder, and 2.0 for both sexes in unipolar disorder. SMR:s for suicide in bipolar disorder were 15.0 for males and 22.4 for females, and in unipolar disorder 20.9 and 27.0 respectively. In bipolar disorder, most extra deaths were caused by natural causes, while in unipolar disorder, unnatural causes caused most extra deaths. Time trends for suicide mortality increased, both for bipolar and unipolar disorder.

SMR:s for suicide for siblings to patients with schizophrenia, bipolar or unipolar disorder were not increased, unless the siblings had a psychiatric diagnosis of their own. Siblings with psychiatric diagnoses had as high suicide mortality as the probands. However, previous suicide in the family increased the suicide risk for patients with schizophrenia and bipolar disorder, but not unipolar disorder.