Pharmacoepidemiology of psychotropic drugs in patients with severe mental disorders in Italy
Objective: To describe the epidemiology of psychotropic drug use in a sample of Italian outpatient psychiatric services. Methods: Drug-utilisation survey conducted within the framework of a broader prospective follow-up study with 67 Italian outpatient psychiatric services. Results: The data concern 2322 patients recruited over a 3-year period. Three-quarters of the cohort were prescribed antipsychotic drugs, one-half received benzodiazepines and nearly one-third received antidepressants. The trends in drug use from 1994 to 1997 show that for patients with schizophrenia there has been a decrease in the prescription of typical neuroleptics: the use of haloperidol passed from 56% to 42.4% and that of chlorpromazine dropped from 13.5% to 6.1%; during the same period, an increasing use of the atypical compound risperidone was observed. Among patients suffering from unipolar affective psychosis, the prescriptions of tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs) have not changed in time, while the proportion of patients receiving neuroleptic drugs has increased from 41% to 45.2%. In addition, the use of antiepileptic drugs and lithium increased, irrespective of diagnosis. Almost 40% of the patients on psychotropic drugs received three or more drugs. Finally, a positive association was found between the number of prescribed compounds and the daily dose administered. Conclusion: These data indicate that in the absence of a rational approach to drug use, a symptomatic approach is generally adopted, by which common sense, experience, information provided by non-independent agencies and other cultural parameters play an important role in the prescription strategy. Pharmacoepidemiology should more often consider the use of drugs as a dependent variable, to be investigated within the context of other clinical, cultural, social and setting-related parameters; this approach would enable a more comprehensive assessment of prescribing practices and strategies in routine clinical care.