ABSTRACT
We provide an overview of research on the epidemiology of autism and related pervasive developmental disorders (PDDs). First, we provide data on the prevalence of autism, which now is estimated to be considerably higher than previously documented. Next, we focus on characteristics associated with autism, including psychosocial correlates, as well as associated physical and medical/psychiatric conditions. In this context, special consideration is given to the coexistence of autism and mental retardation, and to associated conditions that might be the most informative in advancing our understanding of the neurobiology and neuropsychology of autism. Data on outcome are also discussed, with special reference to early intervention and to empirically supported methods. We end by identifying potentially fruitful directions for future epidemiological research on autism/PDD, and by outlining implications of what already is known for the planning and delivery of services for this unique population.
