BackgroundDiscontinuing what is considered the most effective treatment for treatment-resistant schizophrenia may precipitate feelings of failure or a relapse of illness. Clozapine treatment is discontinued for a variety of reasons, including non-adherence, intolerance, or lack of efficacy. Patients’ experiences of discontinuing the “best” treatment and the impact on perceptions of subsequent antipsychotic treatment are important in developing an understanding of the factors affecting people’s treatment choices. This study is the first of its type, seeking to explore people’s perspectives on clozapine discontinuation.MethodSemi-structured interviews with sixteen patients who had received clozapine and discontinued treatment—thirteen males and three females, age range: thirty-two to seventy-eight years old—were audio-recorded and transcribed. A modified inductive approach to analysis, based on grounded theory, was taken to identify commonalities and differences in patients’ perceptions.ResultsThe three main themes identified from participants’ experiences were:positive and negative effects of treatment;feelings of agency, being the capacity to make decisions about treatment and act independently;choice of treatment in the future.Participants exhibited agency in making choices about medication, including risking relapse, while attempting self-management of medication effects. Different participants perceived the same side effect as beneficial or intolerable. Variation in subsequent treatment choices was reported, with some participants favouring depot (long-acting) injections. A participant was frightened when not told about clozapine’s side effects, which led to the participant not being engaged in future treatment decisions. Others, despite suffering serious adverse effects, retained positive perceptions of clozapine; they experienced despair at finding an effective alternative.ConclusionsExperiences with clozapine discontinuation evoked powerful emotions and resulted in clozapine being the benchmark for other treatments. Knowledge, agency, and being in control were important to participants in relation to treatment. Personal perceptions of treatments or beliefs about illness could lead to non-adherence. People value the clinician listening to their experiences to better understand their perspective, enabling concerns about medication to be addressed through true shared decision making.Trial registrationNHS Health Research Authority and Health and Care Research Wales, IRAS Project ID 225753, Research Ethics Committee (REC) reference: 18/NW/0413, 25/06/2018.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12888-023-04851-4.