Mortalité et causes de décès dans la schizophrénie : étude prospective entre dix et 14 ans d’une cohorte de 150 sujets

Abstract

The aim of this study was to quantify the mortality risk in chronic schizophrenic patients, ten to 14 years after the initial evaluation. Furthermore, using sociodemographical, clinical and psychometrical variables evaluated at inclusion, predictors of global or mortality by suicide were explored. One hundred and fifty subjects meeting the research diagnostic criteria (RDC) for chronic schizophrenia were included in the study between 1991 and 1995. At the initial assessment, the following variables were assessed: sex, age, level of education, number of hospitalisations, mean duration of the illness, scores on the physical anhedonia scale, the brief psychiatric rating scale (BPRS), the positive and negative syndrome scale (PANSS), and Beck's depression inventory (BDI). In May 2005, all the subjects were assessed using direct or indirect methods. Survival analysis was conducted using the Kaplan-Meier product-limit estimator and a standardized mortality ratio (SMR) was calculated. Multivariate Cox regression was performed to detect predictive factors associated with mortality. The absolute mortality rate was of 18.57% and the RSM of 4.83. The absolute mortality rate for suicide was 6.98%. Multivariate Cox regression analyses showed that two factors (high rate of males, high dose of antipsychotics) were related to an increase in global mortality risk. Moreover, high dose of antipsychotics and a high rate of "positive" subjects, as evaluated by the PANSS, were related to an increase in mortality risk by suicide. High dose of neuroleptics could characterize the severe form of schizophrenia, the risk of mortality of which was higher than that of the less severe forms. Another explanation was that high doses of neuroleptics could lead to severe side effects and thus an increase in the vulnerability of schizophrenics to organic diseases. Positive, contrary to negative, symptoms could increase the risk of suicide. This 14-year follow-up study confirmed the increased mortality rates by natural and non natural causes observed in chronic schizophrenic subjects.