Abstract
It is important to better understand how adults with autism are functioning in adulthood. Studies that have tracked individuals across the lifespan can help identify developmental factors influence differences in adult outcomes. The present study examines the independence, well-being, and functioning of 123 adults that have been closely followed since early childhood. Autism diagnosis and cognitive assessments were given frequently throughout childhood and during adulthood. We examined differences between adults who had received an autism diagnosis at some point with higher cognitive abilities (Ever ASD-High IQ) and lower cognitive abilities (Ever ASD-Low IQ), as well as adults who never received a diagnosis of autism in the course of the study (Never ASD). We found that autistic features specifically related to adaptive skills and friendships, and verbal intelligence related to work outcomes. In many ways, the Never ASD group had similar outcomes compared to the ASD groups. However, adults with ASD tended to have lower well-being and fewer positive emotions. Families played a major role in supporting adults with and without ASD at all intellectual levels. The findings suggest that realistic ways of increasing independence need to be developed by working with adults and their families, while acknowledging the contribution of individual differences in mental health, intelligence and autism symptoms across neurodevelopmental disorders.