BACKGROUND: Population-based studies comparing the incidence and co-occurring psychiatric conditions of young people without intellectual impairment who are autistic, Attention-Deficit/Hyperactivity Disorder (ADHD), or autistic-ADHD are scarce. For autistic, ADHD, and autistic-ADHD youth in Iceland aged 7-18 years without intellectual impairment, we aimed primarily to estimate the age-standardised incidence of these 3 neurotypes, overall and by sex, and secondarily to estimate the prevalence of…
