Autism spectrum disorder (ASD) is a biologically based neurodevelopmental disorder characterized by impairments in two major domains: 1) deficits in social communication and social interaction and 2) restricted repetitive patterns of behavior, interests, and activities . ASD encompasses disorders previously known as autistic disorder (classic autism, sometimes called early infantile autism, childhood autism, or Kanner's autism), childhood disintegrative disorder, pervasive developmental disorder-not otherwise specified, and Asperger disorder (also known as Asperger syndrome) if the current diagnostic criteria are met. (See "Diagnosis of autism spectrum disorder", section on 'Diagnostic criteria' and "Asperger syndrome (a specific autism spectrum disorder): Clinical features and diagnosis in children and adolescents" and "Asperger syndrome (a specific autism spectrum disorder): Management and prognosis in children and adolescents".).
The rationale for ASD surveillance and screening in primary care will be reviewed here. General developmental screening, ASD-specific screening tests, and clinical features, diagnosis, and management of ASD are discussed separately. (See "Developmental-behavioral surveillance and screening in primary care" and "Screening tools for autism spectrum disorder" and "Clinical features of autism spectrum disorder" and "Diagnosis of autism spectrum disorder" and "Autism spectrum disorder in children and adolescents: Overview of management".)
Autism spectrum disorder — The term "autism spectrum disorder" (ASD) describes a heterogeneous group of neurodevelopmental disorders that have diverse etiologies but are characterized by constellations of symptoms involving impairments in reciprocal social interaction, social communication, and behavior (specifically, restricted, repetitive patterns of behavior, interests, and activities) [1-3].
The terminology and diagnostic criteria for autism spectrum disorder varies geographically.
- The Diagnostic and Statistical Manual of Mental Disorders (DSM) is used predominantly in the United States, and was updated in 2013 (DSM-5) . The DSM-5 diagnosis of ASD encompasses disorders characterized by earlier editions as early infantile autism, childhood autism, Kanner’s autism, high-functioning autism, atypical autism, pervasive developmental disorder-not otherwise specified, childhood disintegrative disorder, and Asperger disorder . Rett syndrome, which had been considered a “pervasive developmental disorder” by the Diagnostic and Statistical Manual, Fourth Edition, Text Revision (DSM-IV-TR) is now considered a separate genetic disorder. (See "Rett syndrome".)
- The World Health Organization International Classification of Diseases, 10th revision (ICD-10) is used in other countries throughout the world . The ICD-10 system classifies ASD as “pervasive developmental disorders, and continues to include several categories (eg, childhood autism, atypical autism, Asperger syndrome, pervasive developmental disorder, unspecified). The 11th Revision of the ICD is expected in 2015.