Abstract
Background
We previously described the high prevalence and burden of significant autistic traits (ATs) in youth with attention-deficit/hyperactivity disorder (ADHD). These traits are associated with significantly greater impairment in psychopathological, interpersonal, educational, and neuropsychological functioning. Because the sample consisted of referred ADHD youth, uncertainty remained regarding whether these findings are generalizable to non-referred populations of youths with and without ADHD.
Objective
The aim of the current study was to assess the prevalence and implications of ATs in a non-referred population of siblings of probands with and without ADHD.
Method
Participants were non-referred siblings of probands with ADHD (N = 257) and control probands (N = 234) of longitudinal, case-control family studies conducted at Massachusetts General Hospital. Assessments included measures of psychiatric, psychosocial, educational, and cognitive functioning. The presence of significant ATs was operationalized using the Child Behavior Checklist AT profile, which consists of combined aggregate T-scores of ≥ 195 on the Withdrawn, Social, and Thought Problems subscales.
Results
ATs were significantly more prevalent among the siblings of probands with ADHD as compared with siblings of control probands (6% vs. 1%; P = .02). Siblings of probands with ADHD with a positive AT profile (N = 15) were significantly more impaired than those without an AT profile (N = 242) with regard to psychopathological, interpersonal, educational, and neuropsychological functioning.
Conclusions
The current study reports a higher-than-expected prevalence of ATs in a non-referred sample of siblings of youth with ADHD, which is consistent with previous findings regarding ATs in a referred sample of youth with ADHD. The presence of ATs is associated with higher levels of morbidity and dysfunction.