Validation of the 36-item and 12-item self-report World Health Organization Disability Assessment Schedule II (WHODAS-II) in individuals with autism spectrum disorder.

Abstract

The World Health Organization Disability Assessment Schedule II (WHODAS-II) is one of the most widely used generic assessments for measuring disability levels in both clinical and nonclinical populations, with sound psychometrics that is also aligned with the International Classification of Functioning framework. However, its psychometric properties have not been explored extensively in individuals with autism spectrum disorder (ASD). This study examined the psychometric properties of the 36-item and 12-item Self-Report WHODAS-II from 109 individuals diagnosed with ASD and without intellectual disability (IQ ≥ 70). Participants were consecutively recruited from the Brain and Mind Centre in New South Wales, Australia. The WHODAS-II showed adequate internal consistency for all domain scores (α = 0.78-0.97 for 36-item) and for the summary scale (α = 0.95 for 36-item; 0.86 for 12-item). All items also exhibited satisfactory correlations with their respective domain (r = 0.39-0.94 for 36-item) and summary scores (r = 0.42-0.71 for 36-item; 0.42-0.67 for 12-item), except item 4.5 "sexual activity" from the 36-item WHODAS-II (r = 0.19). Concurrent validity was shown by moderate correlations between similar constructs across the WHODAS-II and the World Health Organization Quality of Life BREF (Ps < 0.05). The second-order 7-factor model showed the best fit for the 36-item WHODAS-II, while the second-order 6-factor model demonstrated an acceptable fit for the 12-item WHODAS-II. The model fit could be improved with some modifications. The Schmid-Leiman transformation further confirmed the appropriateness of the second-order factor structure. Overall, the results indicated that the WHODAS-II is a viable generic self-report measure for disability in autistic individuals without ID. Autism Res 2019, 12: 1101-1111. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: The majority of autistic people have a disability with a profound or severe limitation in their core activities. However, there is currently limited research identifying reliable and valid self-report measures for disability in the autistic population. This study examined the psychometric properties of the World Health Organization Disability Assessment Schedule II (WHODAS-II) from 109 autistic individuals without intellectual disability. Our results suggest that the WHODAS-II is a viable generic self-report measure for disability in autistic individuals.