Comparison of the 12‐item and 36‐item versions of the World Health Organization Disability Assessment Schedule (WHODAS) 2.0 using longitudinal data from community mental health outreach service users

Aim This study aimed to compare the 12‐item and 36‐item versions of the World Health Organization Disability Assessment Schedule (WHODAS) 2.0 using longitudinal data from community mental health outreach service users. Methods Using data from Tokorozawa City mental health outreach service users in Japan, total and domain WHODAS‐12 and WHODAS‐36 scores were compared. First, we examined score‐change differences by domain at the start of outreach services (T1) and 1 year later (T2) for each version. Next, we compared differences between the two versions using Pearson's correlation, Wilcoxon signed‐rank test, and Bland–Altman analysis. Results Among 20 participants, total scores and scores of some domains (i.e., cognition, getting along, life activities, and participation) were significantly lower at T2 than at T1 on both versions (p