Elsevier

Schizophrenia Research

Volume 45, Issues 1–2, 29 September 2000, Pages 21-28
Schizophrenia Research

Mortality and causes of death in schizophrenia in Stockholm County, Sweden

https://doi.org/10.1016/S0920-9964(99)00191-7Get rights and content

Abstract

A study of mortality for all patients with a first hospital diagnosis of schizophrenia in Stockholm County, Sweden, during 1973 to 1995 was performed, by linking the in-patient register with the national cause-of-death register. Overall and cause-specific standardized mortality ratios (SMR) were calculated by 5-year age classes and 5-year calendar time periods. The number of excess deaths was calculated by reducing the observed number of deaths by those expected. Our results confirmed a marked increase in mortality in schizophrenia both in males and females. Natural (somatic) causes of death was the main cause of excess deaths, with more than half of the excess deaths in females, and almost half of the excess deaths in males. Suicide was the specific cause of the largest number of excess deaths in males, while in females it was cardiovascular disease. SMRs were increased in both natural and unnatural causes of death, with 2.8 for males and 2.4 for females for all deaths, but were highest 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. SMRs in suicide were especially high in young patients in the first year after the first diagnosis.

Introduction

An increased mortality in schizophrenia approximately twice that of the general population has been reported in a number of studies from different countries over a long period of time, and this increase in mortality is still observed (Allebeck and Wistedt, 1986, Alström, 1942, Black and Fisher, 1992, Black and Winokur, 1988, Brown, 1997, Buda et al., 1988, Lindelius and Kay, 1973, Mortensen and Juel, 1993, Ødegård, 1952a, Saugstad and Ødegård, 1979). Important risk modifiers are gender and age at admission (Simpson, 1988). The risk is increased during periods of hospitalization and after the first discharge from hospital (Babigian and Odoroff, 1969, Ødegård, 1952b, Rorsman, 1974). The excessive mortality risk has been primarily attributed to unnatural causes, mainly suicide (Drake et al., 1985, Roy, 1986), but many studies also have reported an increased mortality from natural (somatic) causes (Allebeck and Wistedt, 1986, Herrman et al., 1983, Mortensen and Juel, 1990, Saugstad and Ødegård, 1979). In a meta-analysis of studies on mortality in schizophrenia by Brown (1997), standardized mortality ratios (SMRs) were 1.5 for all causes of death, 1.3 for all natural causes and 4.3 for all unnatural causes of death. The SMR for suicide was 8.4, suicide being the largest single cause of excess mortality.

Although there have been many studies on mortality in schizophrenia, only two have used data from first diagnosed patients (Eastwood et al., 1982, Mortensen and Juel, 1993) which gives the most accurate estimation of mortality rates. Data from patients where follow-up starts later than the first diagnosis will tend to underestimate the mortality rates in suicide in the period close to the first diagnosis (Brown, 1997). The aim of the present study is to assess the mortality among patients with first schizophrenia diagnosis, and specifically to analyze different mortality outcomes such as cancer, cardiovascular disease and suicide; and to what extent gender, age at first diagnosis, duration of follow-up and diagnostic subgroup modified the mortality in the patient group relative to the general population.

Section snippets

Materials and methods

The Swedish psychiatric in-patient register covers all in-patient treatments since 1971. The Stockholm part consists of the psychiatric in-patient treatments from the Stockholm County medical register, which started in 1969 and is complete from 1971. For each hospitalization, the unique national registration number, date of admission and discharge, as well as diagnosis, are registered. No private in-patient facilities exist in Sweden, and the psychiatric in-patient register is therefore

Results

A total of 9162 individuals residing in Stockholm County were discharged at least once with a schizophrenia diagnosis during 1973–95. Of those, 868 had an admission with a schizophrenia diagnosis prior to 1973, and 510 were residing outside Stockholm County at the first schizophrenia admission and were excluded. Thus, 7784 individuals (3929 males and 3855 females) with a first schizophrenia diagnosis were included in the study. In males, first admission was most common at <30 years of age,

Discussion

Our main finding was that, despite higher SMRs for unnatural than for natural causes of death, the total number of excess deaths was larger for natural than for unnatural causes for females and of the same magnitude for males. The largest single cause of death was cardiovascular disease followed by suicide, in both males and females. Cardiovascular disease was the main cause of excess deaths in females, while in males this was the case with suicide. The number of excess deaths, rather than

Conclusion

This study confirmed a marked increase in standardized mortality ratios in schizophrenia both in males and females. Mortality was increased in natural as well as unnatural causes of death, with an increased mortality by natural causes as the main cause of excess deaths. Mortality ratios for suicide were very high, particularly in young age and in the first year after the first schizophrenia admission. These results are important for planning preventive measures and improvement of the

Acknowledgements

This study was supported by grants from Stockholm County Council. We want to thank our reviewers for a valuable comment on the non-differential effect of smoking on SMR for cardiovascular, cerebrovascular and respiratory disease. We are also indebted to professors Lars Terenius and Göran Sedvall, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm for useful opinions and critical revisions of the manuscript.

References (27)

  • N.E. Breslow et al.
    (1987)
  • S. Brown

    Excess mortality of schizophrenia: a meta-analysis

    Br. J. Psychiatry

    (1997)
  • M. Buda et al.

    Causes of death in DSM-III schizophrenics and other psychotics (atypical group): a comparison with the general population

    Arch. Gen. Psychiatry

    (1988)
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