Adaptive Functioning during the Transition to Adulthood and Beyond

Background: Cross-sectional studies indicate a cognitive functioning advantage over adaptive functioning that widens with age, and this pattern seems to be unique to autism spectrum disorder (ASD; Kanne et al., 2011). However, this pattern has been understudied during the transition to adulthood.

Objectives: To examine relative performance on Vineland Adaptive Behavior Scales, Second Edition (Vineland-II) domains by age and cognitive ability groups in a sample of older adolescents and adults with ASD. 

Methods: Participants were 75 adolescents and adults (age M = 24.22, SD = 8.98, range = 16.08 to 58.17; 61 male) with a clinical DSM-IV diagnosis of Autistic Disorder, Asperger’s Disorder, or PDD-NOS. All participants met criteria for Autism or Autism Spectrum on the Autism Diagnostic Observation Schedule (ADOS; Lord, Rutter, & DiLavore, 1999; Lord et al., 2012). Participants were predominantly Caucasian and from middle- to upper-middle class families. The Kaufmann Brief Intelligence Test, Second Edition (KBIT-2) was administered to each participant. A parent or caregiver of each participant completed the Vineland-II. Retrospective chart review was conducted using de-identified data. All assessments were administered for clinical purposes and/or IRB-approved research projects at an autism center in the Southwestern United States.

Results: Results of separate mixed ANCOVAs are reported in Table 1. Composite IQ scores were significantly higher than standard scores for communication, daily living skills (DLS), and socialization in the full sample. Communication and socialization scores were significantly lower than DLS scores, but there was no difference between communication and socialization scores. Vineland-II performance profiles differed significantly among age groups, but not intellectual ability groups. In adolescents, DLS scores did not differ significantly from communication scores and were only marginally higher than socialization scores. Socialization scores were significantly lower than communication scores among adolescents and adults, but not young adults.

Conclusions: IQ scores were significantly higher than all adaptive functioning domains in each age group. Although the majority of the sample had IQs in the average to above average range, average VABS domain standard scores were below 70 in all cognitive ability groups. Despite having similar IQ scores, adolescents had significantly higher average VABS domain scores than young adults and adults, which supports previous suggestions that the gap between cognitive and adaptive functioning skills continues into adulthood and increases with age (Kanne et al., 2011). DLS were observed to be a relative strength in young adults and adults, but not adolescents. The three groups did not differ in DLS; instead, adolescents had higher communication and socialization scores than young adults and adults. Standard scores represent functioning relative to same-age peers. Findings suggest that DLS continue to develop post-adolescence in individuals with ASD, whereas development of age-appropriate communication and socialization skills appears to slow with age. Relative performance on Vineland-II subdomains will also be presented. Together, findings provide valuable information regarding developmental trajectories of adaptive functioning skills, adult outcomes, and intervention targets for improving adult outcomes.