Delays and barriers to the commencement of clozapine in eligible people with a psychotic disorder: A literature review

Abstract

Aim: While the majority of individuals with a first episode of psychosis (FEP) achieve symptomatic remission with the appropriate treatment, there is a small but significant proportion who do not achieve remission of symptoms despite adequate treatment with at least two antipsychotic medications (termed treatment resistance). Clozapine is indicated in individuals who fulfil the criteria for treatment-resistant schizophrenia, however, despite it being the most effective antipsychotic medication, there can be delays in the commencement of clozapine in eligible patients. Methods: A systematic search was performed to identify articles reporting either the time taken to commence clozapine (or delays) in eligible individuals or articles reporting barriers to the commencement of clozapine. The initial search generated 5588 articles and of these, 18 were eligible. Results: 13 studies described delays in commencing clozapine and five studies reported on the barriers to the commencement of clozapine. The duration of delay from when an individual was deemed eligible for clozapine treatment to the time of clozapine commencement ranged from 19.3 weeks to 5.5 years. In addition, the duration of illness prior to clozapine initiation ranged from 1.1 to 9.7 years. It was found that some clinicians were more inclined to prescribe antipsychotic polypharmacy or doses higher than recommended than to prescribe clozapine. Conclusions: Delays in commencing clozapine have been consistently demonstrated. Early intervention for psychosis services are the ideal settings to identify individuals with persistent positive psychotic symptoms and commence clozapine if indicated.