Objective: The course of behavioral change in autistic behaviors has received little attention in previous research but is a potentially important parameter for study in autism.
Method: Autistic behaviors were systematically examined in 38 high-IQ adolescent and adult autistic individuals at their current age (13 through 28 years) and retrospectively at age 5 years using a standardized interview for autism.
Results: Significant change over time in autistic behaviors, generally in the direction of improvement, was detected. The proportion of subjects showing improvement in communication and social behaviors was found to be significantly higher than the proportion showing improvement in ritualistic/repetitive behaviors. Five of 38 subjects who met DSM-IV criteria for autistic disorder at age 5 years no longer met criteria at their current age, although all five continued to have substantial impairment.
Conclusions: The study of patterns of behavioral change over time in autism has practical implications for both diagnosis and prognosis as well as potential importance in defining biologically meaningful subgroups and clarifying fundamental mechanisms underlying this disorder.