Objective: To explore the pattern of clozapine use in persons with severe mental illness and in persons with Parkinson's disease and the characteristics associated with early discontinuation in naturalistic conditions.
Method: A historical fixed cohort study of persons newly treated with clozapine was performed on a representative community-based sample of persons affiliated to the French health insurance system (n = 611,393). Treatment for Parkinson's disease was used as a proxy for this condition and lack of such treatment as a proxy for severe mental illness (SMI).
Results: The prevalences of antipsychotic and clozapine use were 4.4% and <0.1% respectively. Of the 237 persons with a new outpatient prescription of clozapine, 25% were prescribed an antiparkinsonian treatment. In persons with SMI, the median duration of the index episode of clozapine treatment was 4.9 months (Interquartile range 1.0-20.5). Longer duration was independently associated with coprescription of anxiolytics or antidepressant. Few new additions of antipsychotics were observed during the clozapine episode.
Conclusion: Efforts have to be made to optimize clozapine treatment in real-world conditions. Considering the high frequency of persons with Parkinson's disease among clozapine users, further studies have to be performed in this population.
Keywords: clozapine; health insurance database; treatment duration.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.