Autism-Related Variation in Reciprocal Social Behavior: A Longitudinal Study.

Deficits in reciprocal social behavior are a characterizing feature of autism spectrum disorder (ASD). Autism-related variation in reciprocal social behavior (AVR) in the general population is continuously distributed and highly heritable-a function of additive genetic influences that overlap substantially with those which engender clinical autistic syndromes. This is the first long-term prospective study of the stability of AVR from childhood through early adulthood, conducted via serial ratings using the Social Responsiveness Scale, in a cohort-sequential study involving children with ASD, other psychiatric conditions, and their siblings (N = 602, ages = 2.5-29). AVR exhibits marked stability throughout childhood in individuals with and without ASD.