Validity and Reliability of the Japanese Version of the 12-item Self-administered World Health Organization Disability Assessment Schedule (WHODAS) 2.0 in Patients with Schizophrenia.

It is necessary to assess functional impairment when treating schizophrenia. The World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) has been adopted as a measure of functional disability in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. This study was a secondary analysis from a cross-sectional study of health-related behaviors among patients with schizophrenia. We examined the validity and reliability of the Japanese version of the 12-item WHODAS 2.0 when self-administered by such patients. Participants were 350 outpatients with schizophrenia from a psychiatric hospital. The standard six-factor structure of the WHODAS 2.0 showed a good fit for these participants. The Cronbach's alpha coefficient was 0.858, showing good internal consistency. The WHODAS 2.0 showed moderate correlations with the modified Global Assessment of Functioning and Kessler 6 scales (r=-0.434 and 0.555, respectively). The results of this study show that the Japanese version of the 12-item self-administered WHODAS 2.0 has good internal consistency and convergent validity among patients with schizophrenia. Further exploration of the usefulness of WHODAS 2.0 in clinical settings is needed.