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The aim of this study was to (1) calibrate an item bank to measure patients’ experience of drug therapy for adult patients with SMIs and (2) develop computerized adaptive testing (CAT) to improve its use in routine practice. This is a cross-sectional, multicentric study involving 541 patients with schizophrenia, bipolar disorder, and major depressive disorder. Analyses based on classical test and item response theories were performed. After 7 highly inter-correlated items and 4 items with low factor loadings were removed, the remaining 26 items were sufficiently unidimensional (RMSEA = 0.069, CFI = 0.969, TLI = 0.963) and showed adequate fit to the generalized partial credit model. There was no differential item functioning by gender, age, care setting, or diagnosis from moderate- to large-magnitude. The mean score was 46.0 ± 16.9 and was significantly higher for patients reporting good medication adherence. The resulting PREMIUM-DT item bank has strong psychometric properties, and CAT facilitates widespread use in clinical settings (an average of 8 items administered, corresponding to a reliability of >0.90). Our results suggest that practical information and information about the side effects of psychotropic treatments and how to cope with them should be targeted as a priority to improve patients’ experience of drug therapy., Competing Interests: The authors report no conflict of interest in this work.

Most patient-reported experience measures (PREMs) are paper-based, leading to a high burden for patients and care providers. The aim of this study was to (1) calibrate an item bank to measure patients' experience of respect and dignity for adult patients with serious mental illnesses and (2) develop computerized adaptive testing (CAT) to improve the use of this PREM in routine practice. Patients with schizophrenia, bipolar disorder, and major depressive disorder were enrolled in this multicenter and cross-sectional study. Psychometric analyses were based on classical test and item response theories and included evaluations of unidimensionality, local independence, and monotonicity; calibration and evaluation of model fit; analyses of differential item functioning (DIF); testing of external validity; and finally, CAT development. A total of 458 patients participated in the study. Of the 24 items, 2 highly inter-correlated items were deleted. Factor analysis showed that the remaining items met the unidimensional assumption (RMSEA = 0.054, CFI = 0.988, TLI = 0.986). DIF analyses revealed no biases by sex, age, care setting, or diagnosis. External validity testing has generally supported our assumptions. CAT showed satisfactory accuracy and precision. This work provides a more accurate and flexible measure of patients' experience of respect and dignity than that obtained from standard questionnaires.