Purpose: To develop and evaluate a self- and observer-rating scale on quality of life in patients suffering from schizophrenia with regard to the efficacy of atypical antipsychotics based on different dimensions and to apply within a pilot study.
Methods: Following review of existing scales and a prevalidation phase, the Riedel-Spellmann-Musil (RSM) scale was developed comprising 36 items assigned to different subscales. As reference scales, the Quality of Life Scale (QLS) and the Subjective Well-being Under Neuroleptic Treatment Scale-short version (SWN-K) were performed, psychopathology and adverse events were measured at all visits. Reliability was assessed using Cronbach's alpha, Pearson's correlation coefficients were used to assess construct validity, and Intraclass Correlation Coefficients (ICCs) were used for test-retest reliability. T tests were performed in normal distributed samples; otherwise Wilcoxon tests were used.
Results: One hundred and thirty-six patients were included in the study. Cronbach`s α was 0.917 for the self-rating and 0.915 for the interviewer-rating part. ICCs were >0.70 for all subscales. The self-rating part correlated strongly with the SWN-K and the observer part with the QLS. Changes in psychopathology over the study period and different levels of functioning were detected.
Conclusion: The RSM-scale is a new scale to assess the quality of life in different dimensions of patients with schizophrenia treated with antipsychotics and shows good internal consistency, test-retest reliability, construct and discriminant validity.