Adherence to treatment guidelines in clinical practice: study of antipsychotic treatment prior to clozapine initiation

Background Clozapine is the only antipsychotic drug licensed for treatment-resistant schizophrenia but its use is often delayed. Since previous studies, national guidelines on the use of clozapine and other antipsychotics have been disseminated to clinicians. Aims To determine the theoretical delay to clozapine initiation and to quantify the prior use of antipsychotic polypharmacy and high-dose antipsychotic treatment. Method Clinico-demographic data were extracted from the treatment records of all patients commencing clozapine in our centre between 2006 and 2010. Results Complete records were available for 149 patients. The mean theoretical delay in initiating clozapine was 47.7 months (s.d.=49.7). Before commencing clozapine, antipsychotic polypharmacy and high-dose treatment was evident in 36.2 and 34.2% of patients respectively. Theoretical delay was related to illness duration (beta=0.7, P<0.001) but did not differ by gender or ethnicity. Conclusions Substantial delays to clozapine initiation remain and antipsychotic polypharmacy and high doses are commonly used prior to clozapine, despite treatment guidelines.