Validation of a Japanese Version of the Vineland Adaptive Behavior Scales, Second Edition: Comparison Between ASD, ADHD, and Intellectual Disability

Background: Currently, a comprehensive adaptive behavior scale that assists in making a decision on the necessary level of support for individuals with disabilities is not available in Japan. The unavailability of adaptive behavior scales has led to an underestimation of the needs related to the adaptive functioning of individuals with disabilities, particularly those who exhibit a significant discrepancy between their cognitive ability and adaptive functioning (i.e., those who exhibit higher IQ but have deficits in adaptive functioning). The Vineland Adaptive Behavior Scales, Second Edition (VABS-II; Sparrow, Cicchetti, & Balla, 2005) is one of the most widely used adaptive behavior scales in the US and other countries, and it is used for not only identifying individuals with cognitive disabilities but also for assessing needs of individuals with autism spectrum disorders (ASD) and other developmental disabilities. We started a standardizing process of the Japanese version of the VABS-II.

Objectives: As a part of the validation analysis, this study aimed to compare the scale scores of the Japanese version of the VABS-II among three groups: the ASD group, the attention deficit hyperactivity disorder (ADHD) group, and the intellectual disability (ID) group. 

Methods: The participants of the ASD group (n = 132), the ADHD group (n = 21), and the ID group (n = 52) received a diagnosis on the basis of the DSM-IV criteria by experienced psychiatrists belonging to medical and educational facilities in 28 areas throughout Japan. We administered the Japanese version of the VABS-II to parents, caregivers, or adult family members of the participants.

Results: With regard to the adaptive behavior domains, the ID group showed the lowest scores in all subdomains. The ASD groups showed lower scores than the ADHD group, especially in the Communication and Socialization domains. In the context of the maladaptive behavior domains, the differences between the three groups were smaller than those in the adaptive behavior subscales. In particular, in the external problem subscale, the ADHD group showed a higher mean score than the other two groups, although it was not statistically significant.

Conclusions: We found that the Japanese version of the VABS-II is quite useful for evaluating the actual adaptive functioning of individuals with developmental and intellectual disabilities.