Determinants of patient satisfaction in clozapine users: results from the Clozapine International Consortium (CLOZIN)

Clozapine is highly effective for treatment-resistant schizophrenia but is underutilized due to patient and clinician-related concerns. Little is known about the general level of patient satisfaction with clozapine and determinants thereof. We therefore explored determinants of patient satisfaction with clozapine in individuals diagnosed with schizophrenia spectrum disorders (SSDs). Cross-sectional data from 480 clozapine users were used to examine demographic and clinical factors, including symptom severity, treatment response, and adverse drug reactions (ADRs). Patient satisfaction was self-rated on a scale of 1 to 10. Results showed a mean satisfaction score of 7.4 (SD = 1.9), with significant associations between satisfaction and treatment response (B = 0.42, R² = 0.19, p = 3.9 × 10⁻¹⁸), symptom severity (B = 0.10, R² = 0.05, p = 2.06 × 10-9), occurrence of ADRs (B = −0.16, R² = 0.06, p = 3.2 × 10-5), and recreational drug use (B = −1.32, R² = 0.05, p = 2.09 × 10-4). Hypersalivation and prolonged sleep duration were the only ADRs linked to lower satisfaction (B = −0.72, R² = 0.06, p = 3.5 × 10-5 and B = −0.57, R² = 0.04, p = 1.4 × 10-3, respectively). Despite concerns about ADRs, treatment effectiveness showed a stronger association with patient satisfaction among clozapine users than the occurrence of ADRs. In conclusion, our findings suggest that strategies aimed at bolstering clozapine’s effectiveness may help counter worldwide underprescription rates of clozapine in patients with SSDs.