Editorial: Important First Look at Population-Based Trajectories of Youths With Autism

Few studies have followed young people with autism spectrum disorder (shortened to "autism" herein) over time, and all previous longitudinal studies have used clinical or center-based samples,^1,2 leaving considerable uncertainty about the course of autism in the general population. In this issue, Simonoff and colleagues³ describe the first longitudinal study within a population-based sample, the Special Needs and Autism Project (SNAP) cohort. By assessing adolescents and young adults with autism at 3 time points over 11 years, from approximately 12 to 23 years of age, the authors profiled the trajectories of both cognitive and autism symptoms. Despite little change in caregiver-rated autism symptoms over this time period, they found that full-scale IQ (FSIQ) showed a moderate increase, with some hints of factors that may predict greater improvement.