Autism is one of five disorders that falls under the umbrella of Pervasive Developmental Disorders (PDD), a category of neurological disorders characterized by “severe and pervasive impairment in several areas of development.”
The five disorders under PDD are:
Each of these disorders has specific diagnostic criteria which been outlined in the American Psychiatric Association's Diagnostic & Statistical Manual of Mental Disorders (DSM-IV-TR).
Prevalence of Autism
Autism is the most common of the Pervasive Developmental Disorders, affecting an estimated 1 in 150 births (Centers for Disease Control Prevention, 2007). Roughly translated, this means as many as 1.5 million Americans today are believed to have some form of autism. And this number is on the rise.
Based on statistics from the U.S. Department of Education and other governmental agencies, autism is growing at a startling rate of 10-17 percent per year. At this rate, the ASA estimates that the prevalence of autism could reach 4 million Americans in the next decade.
Autism knows no racial, ethnic, social boundaries, family income, lifestyle, or educational levels and can affect any family, and any child.
And although the overall incidence of autism is consistent around the globe, it is four times more prevalent in boys than in girls.