WHODAS II: Contribution to the Validation of the Italian Version

Based on the World Health Organization’s current thinking about functioning and disability, and on the biopsychosocial model of disability promoted by the International Classification of Functioning, Disability, and Health, the WHO’s Disability Assessment Schedule II (WHODAS II) has been developed to assess the activity limitations and participation restrictions, experienced by an individual in six activity domains of everyday life, irrespective of medical diagnosis. Our study provides a contribution to the validation of the Italian version of the WHODAS II. The questionnaire has been administered to a sample of 606 subjects (240 males and 366 females, ranging in age from 18 to 89 years; mean=39,68; std. deviation=19,96). In order to assess the validity of the Italian adaptation of the tool a factor analysis (Principal Component Analyses) was performed. This analyse shows a good correspondence with the original structure. Furthermore, the internal consistency of most of subscales, estimated by means of the Cronbach’s alpha, was found to be high in the examined sample. For the most part, the results confirm the presence of six factors, according to the six activity domains expected to be assessed by the questionnaire. Some cross-loadings were also obtained since some items have a strong relationship with more than one factor: this is plausible as regards content, since some areas mutually determine each other. We conclude that WHODAS II Italian version appears to be a useful psychometric tool for measuring functioning and disability; it is reliable, valid and applicable across different disorders.