Autistic adults have faced well-documented barriers to education and employment, yet whether these translate into differences in cognitive reserve (CR) and cognitive aging remains unclear. The first formally diagnosed cohorts are now reaching older age and research is pointing to elevated dementia risk in this population. This makes understanding what drives or protects against cognitive decline in autism increasingly urgent.

This study examined whether CR proxies differed between autistic and neurotypical (NT) adults, whether they predicted baseline cognitive performance and cognitive change, and whether diagnostic group moderated these associations. Data were drawn from one of the largest longitudinal studies on cognitive aging in autistic adults, with 83 participants assessed across two waves approximately six years apart. CR was operationalized through educational attainment and occupational complexity, with verbal fluency and verbal memory as cognitive outcomes.

Autistic adults had a significantly higher change of being employed in lower complexity occupations than NT adults, however no significant group difference emerged for educational attainment. Educational attainment predicted baseline performance across all cognitive outcomes, most robustly for letter fluency, while occupational complexity did not predict baseline performance on any outcome. Neither proxy predicted cognitive change over time, and no moderation by diagnostic group was found.

These findings suggest that CR proxies are more strongly associated with where people start cognitively than with how they decline over time, consistent with recent large-scale longitudinal evidence in NT aging. No evidence was found, however, that CR operates in a different way for autistic adults than in NT adults. The occupational gap observed despite comparable IQ points to structural barriers rather than cognitive differences as the driving force. Large-scale, representative studies with richer CR measures will be essential to build a clearer picture of cognitive resilience in autistic aging.