ABSTRACT
The Diagnostic and statistical manual of mental disorders (American Psychiatric Association (APA), 2000) includes three related conditions that comprise the “autism spectrum”: autism, Asperger’s disorder, and pervasive developmental disorder not otherwise specified. The DSM-IV-TR in fact delineates five distinct pervasive developmental disorders (PDDs), the other two being Rett’s disorder and childhood disintegrative disorder. All of these are characterized by “severe and pervasive impairment in several areas of development: reciprocal social interaction, communication skills, or the presence of stereotyped behavior, interests, and activities” (APA, 2000, p. 65). They are evident in the first few years of life and are often associated with some degree of mental retardation. First identified by Leo Kanner in 1943, autism is the best known of these conditions, but in the past several decades researchers have noted that the three PDDs noted above may in fact represent different disability levels of the same core condition. These have come to be known as the autism spectrum disorders (ASDs). For several reasons (noted below) the spectrum conditions have been increasingly diagnosed, and because they require such intensive intervention, often with modest impact, they represent a great challenge for service providers, resource developers, and health care funders.
