Predictive factors of the number and the dose of anti-psychotics in a cohort of schizophrenic patients

Background Anti‐psychotic prescription in schizophrenia is characterised in Europe by frequent associations and high doses. Nevertheless, few longitudinal epidemiological studies have explored anti‐psychotic prescriptions. Aim (1) To describe the evolution of prescription patterns across time; (2) to determine risk factors for prescription of high doses of anti‐psychotics and for anti‐psychotic combinations. Materials and Methods Three thousand four hundred seventy three subjects were included in 1993. Data collected in 1993 and subsequently in 1996 and 1999, provided information on demographics, clinical status and prescription. In 1996, the response rate was 68.5% and 56.7% in 1999. Results The number of anti‐psychotics prescribed slightly decreased across time, while doses remained high for one‐third of the patients. The factors predicting dose were: dose at previous evaluation, class of anti‐psychotic and clinical severity. The factors predicting the number of anti‐psychotics were: previous number and class of anti‐psychotic and clinical severity. Conclusion Higher dosage and combinations were related more to physicians' habits than to patient characteristics, as is frequently observed in chronic disease. Copyright © 2005 John Wiley & Sons, Ltd.