Clozapine Discontinuation: A Quantitative and Qualitative Review in New Zealand

Abstract

Schizophrenia is a debilitating mental illness. Up to 30% of people with schizophrenia do not respond to usual treatment. Approximately 60% of people with treatment resistant schizophrenia will respond to clozapine. While antipsychotics can provide effective symptom control, relapse is common in those who stop treatment. Little research has been undertaken to identify why people stop taking clozapine, or the factors that influence their decision to stop. This research aims to fill that gap. Objectives: To establish the discontinuation rate and documented reasons for discontinuation of clozapine in the New Zealand public health system. To explore the experiences of people receiving clozapine treatment from the perspectives of those who continue and those who discontinue treatment. Methods: A retrospective file audit was conducted of all adults prescribed clozapine over a two year period within one District Health Board in the Auckland region. Data collected included demographics, diagnosis, comorbid conditions, duration of mental illness, clozapine dose, concomitant antipsychotics, stop-restart episodes, discontinuations, and reasons for these. Key-informant interviews were conducted in a small group of people who had been prescribed clozapine. A semi-structured interview format was used and analysis was by a general inductive approach. Results: In a cohort of 396 people prescribed clozapine a continuation rate of 93.2% was found over the two year study period. The most common reason for discontinuation was adverse effects (33.3%) and this decision was most frequently made by the client (29.6%). Three themes important to clozapine discontinuation were identified from interviews with 17 people: control, describing the concept of autonomy over one’s own treatment; balance, the trade off between positive and negative experiences and the perceptions of these; and insight, the development and change in those who stopped and restarted clozapine. Conclusion: The majority of those established on clozapine will continue this treatment. Those who discontinued most often did so due to adverse effects. Acknowledging a person’s perceptions of medication experiences, both positive and negative, and working collaboratively may allow people to exercise some autonomy over their treatment through shared decision making, without this leading to medication discontinuation.