Limited Discrepancy Between Cognitive Ability and Daily Living Skills in Autism: A Longitudinal Study From Ages 2-25.

Many autistic individuals with average or higher cognitive abilities (also referred to as intelligence quotient; IQ) exhibit weaker than expected daily living skills (DLS). However, existing evidence is primarily cross-sectional. This study examined: (1) how IQ-DLS discrepancies develop from early childhood through early adulthood, (2) whether childhood factors (e.g., autism features, non-verbal IQ) predict these developmental pathways, and (3) how IQ-DLS discrepancy trajectories relate to adult experiences (e.g., employment, well-being, relationships). Analyses included 92 individuals from the Longitudinal Study of Autism with average or better IQ and repeated assessments of IQ and DLS from ages 2-25 years. Developmental patterns in IQ-DLS discrepancy scores were identified using group-based trajectory modeling. Two trajectory groups were identified: IQ = DLS (commensurate cognitive and daily living skills) and IQ > DLS (weaker DLS than expected for IQ). Most participants had commensurate IQ and DLS across development. When discrepancies emerged, they did so gradually, becoming apparent by mid-childhood. White participants were more likely to be in the IQ > DLS group; participant race was the only early childhood predictor of group membership. IQ-DLS discrepancy trajectories were not significantly associated with adult experiences. In contrast to existing literature, this study suggests autistic individuals with average or higher IQ may not always have persistent deficits in DLS relative to cognitive ability. When discrepancies occurred in this sample, they developed over time rather than being present from early childhood. These findings challenge deterministic assumptions about adaptive function in autism and highlight the importance of sustained opportunities to learn and practice DLS across development.