Effects of stringent criteria on eligibility for clozapine among public mental health clients

OBJECTIVE: This study estimated rates of eligibility for treatment with clozapine among clients in a public mental health system using criteria with various degrees of restrictiveness. METHODS: A stratified, random cluster sample of 293 clients was selected from among all clients with schizophrenic disorders known to the mental health system of the city and county of San Francisco during 1991. Data on variables associated with eligibility for clozapine were abstracted from clinical records, and eligibility was estimated using broad and stringent criteria. RESULTS: An estimated 42.9 percent of the clients were eligible for clozapine using broad eligibility criteria that included a diagnosis of schizophrenia or schizoaffective disorder, two previous neuroleptic trials of at least 600 mg per day chlorpromazine equivalents for at least four weeks or tardive dyskinesia, Global Assessment of Functioning score less than 61, and no contraindications. Eliminating eligibility due to tardive dyskinesia alone, excluding persons with schizoaffective disorder, requiring six-week medication trials, and requiring three adequate medication trials instead of two resulted in substantial reductions in the rate of eligibility. CONCLUSIONS: Varying interpretations of the criteria for clozapine treatment listed in the medication package insert dramatically affect patients' eligibility for clozapine. Mental health agencies should endeavor to maintain a balance between restricting use of clozapine due to cost and providing it to the full spectrum of patients who might benefit from the medication.