Predictive utility of autistic traits in youth with ADHD: a controlled 10-year longitudinal follow-up study.

The objective of this study was to investigate the stability and predictive utility of autistic traits (ATs) in youth with attention-deficit/hyperactivity disorder (ADHD). Participants were referred youth with and without ADHD, without a diagnosis of autism spectrum disorder, and their siblings, derived from identically designed longitudinal case-control family studies of boys and girls with ADHD. Subjects were assessed with structured diagnostic interviews and measures of social, cognitive, and educational functioning. The presence of ATs at baseline was operationalized using a unique profile of the Child Behavior Checklist (CBCL) consisting of an aggregate T score of ≥ 195 on the Withdrawn, Social, and Thought Problems subscales (CBCL-AT profile). At the follow-up, 83% of the ADHD youth with a positive AT profile at baseline continued to have a positive CBCL-AT profile. The presence of a positive CBCL-AT profile at baseline in youth with ADHD heralded a more compromised course characterized by a greater burden of psychopathology that emerged at an earlier age, along with poorer interpersonal, educational, and neurocognitive outcomes. Findings indicate a high level of persisting ATs in ADHD youth over time, as indexed through the CBCL-AT profile, and the presence of this profile prognosticates a compromised course in adult life in multiple domains of functioning.