CAUSES OF DEATH ASSOCIATED WITH PSYCHIATRIC-ILLNESS

Background A prospective cohort analysis of mortality, among entrants to a population-based psychiatric case register, was undertaken to ide ntify specific causes of death responsible far the increased risk of m ortality previously reported in this large group of unselected patient s. Methods The analysis was based on a study population of 16871 cases , aged 15-89 years, from Worcester and Kidderminster Health Districts, entering the case register between 1974 and 1984 and generating a tot al of 85 073 patient-years (PYR) of observation. The underlying cause of death was coded to the relevant revision of the International Class ification of Diseases (ICD). Numbers of deaths observed in the study p opulation were compared with the number of deaths expected on the basi s of mortality rates for England and Wales. Comparisons were made for eight main causes of death, aggregated at Chapter level of the ICD, an d 11 categories of psychiatric diagnoses. Two indices of mortality wer e used for evaluation: relative risk (RR) = observed deaths/expected d eaths; and excess mortality rate (EMR)=(observed - expected deaths)/PY R. Results RRs were significantly raised for accidents, including suic ides, as anticipated, and for various main causes of death. The increa sed risk of accidental death was found across the majority of the 11 p sychiatric diagnostic groups although the EMRs were low at less than 5 /1000 PYR. Deaths from respiratory disorders gave rise to the highest RRs after accidental deaths, and were responsible for substantial exce ss mortality among in-patients and patients with psychotic illnesses ( especially dementia). The largest numbers of deaths of both sexes were due to diseases of the circulatory system, with a 40 per cent excess at observed over expected Values in the whole series. The excess was d ue mainly to deaths of in-patients and of patients with psychotic diag noses. No excess of deaths owing to neoplasms was found for either in- patients or out-patient groups. Conclusions The findings that psychiat ric illness is associated with an increased risk of death from 'natura l' causes and that the level of risk was related to the severity and t o the diagnostic category of the illness have implications for pattern s of care and use of resources.