Clinical practice variations in prescribing antipsychotics for patients with schizophrenia

Few studies have examined the variations among individual physicians in prescribing antipsychotics for schizophrenia. This study examined clinical practice variations in the route and dosage of antipsychotic medication prescribed for inpatients with schizophrenia by 11 different psychiatrists. The sample consisted of 130 patients with a DSM-III-R diagnosis of schizophrenia who had received inpatient care at a state hospital or Veterans Affairs medical center in the southeastern United States in 1992-1993. Mixed-effects regression models were developed to explore the influence of individual physicians and hospitals on route of antipsychotic administration (oral or depot) and daily antipsychotic dose, controlling for patient case-mix variables (age, race, sex, duration of illness, symptom severity, and substance-abuse diagnosis). The average daily antipsychotic dose was 1092 +/- 892 chlorpromazine mg equivalents. Almost half of the patients (48%) were prescribed doses above or below the range recommended by current practice guidelines. The proportion of patients prescribed depot antipsychotics was significantly different at the 2 hospitals, as was the antipsychotic dose prescribed at discharge. Individual physicians and patient characteristics were not significantly associated with prescribing practices. These data, which were obtained before clinical practice guidelines were widely disseminated, provide a benchmark against which to examine more current practice variations in antipsychotic prescribing. The results raise several questions about deviations from practice guidelines in the pharmacological treatment of schizophrenia. To adequately assess quality and inform and possibly further develop clinical practice guideline recommendations for schizophrenia, well-designed research studies conducted in routine clinical settings are needed.