page_title: Autism spectrum
section_title: Diagnosis
hierarchical_section_title: Autism spectrum / Diagnosis
caption_attribution_description: English: Process for screening and diagnosing Autism Spectrum Disorder; ASD - Autism Spectrum Disorder; M-CHAT - Modified Checklist for Autism in Toddlers; (+) - positive test result; (-) - negative test result
context_page_description: The autism spectrum encompasses a range of neurodevelopmental conditions, including autism and Asperger syndrome, generally known as autism spectrum disorders. Individuals on the autistic spectrum experience difficulties with social communication and interaction and also exhibit restricted, repetitive patterns of behavior, interests, or activities. Symptoms are typically recognized between one and two years of age. Long-term problems may include difficulties in performing daily tasks, creating and keeping relationships, and maintaining a job.
  The cause of autism spectrum conditions is uncertain. Risk factors include having an older parent, a family history of autism, and certain genetic conditions. It is estimated that between 64% and 91% of risk is due to family history. Diagnosis is based on symptoms. In 2013, the Statistical Manual of Mental Disorders version 5 replaced the previous subgroups of autistic disorder, Asperger syndrome, pervasive developmental disorder not otherwise specified, and childhood disintegrative disorder with the single term "autism spectrum disorder".
context_section_description: ASD can be detected as early as 18 months or even younger in some cases. A reliable diagnosis can usually be made by the age of two years, however, because of delays in seeking and administering assessments, diagnoses often occur much later. The diverse expressions of ASD behavioral and observational symptoms and absence of one specific genetic or molecular marker for the disease pose diagnostic challenges to clinicians who use assessment methods based on symptoms alone. Individuals with an ASD may present at various times of development (e.g., toddler, child, or adolescent), and symptom expression may vary over the course of development. Furthermore, clinicians who use those methods must differentiate among pervasive developmental disorders, and may also consider similar conditions, including intellectual disability not associated with a pervasive developmental disorder, specific language disorders, ADHD, anxiety, and psychotic disorders. Ideally the diagnosis of ASD should be given by a team of professionals from different disciplines (e.g. child psychiatrists, child neurologists, psychologists) and only after the child has been observed in many different settings.
  Considering the unique challenges in diagnosing ASD using behavioral and observational assessment, specific practice parameters for its assessment were published by the American Academy of Neurology in the year 2000, the American Academy of Child and Adolescent Psychiatry in 1999, and a consensus panel with representation from various professional societies in 1999. The practice parameters outlined by these societies include an initial screening of children by general practitioners (i.e., "Level 1 screening") and for children who fail the initial screening, a comprehensive diagnostic assessment by experienced clinicians (i.e. "Level 2 evaluation"). Furthermore, it has been suggested that assessments of children with suspected ASD be evaluated within a developmental framework, include multiple informants (e.g., parents and teachers) from diverse contexts (e.g., home and school), and employ a multidisciplinary team of professionals (e.g., clinical psychologists, neuropsychologists, and psychiatrists).
  As of 2019, psychologists would wait until a child showed initial evidence of ASD tendencies, then administer various psychological assessment tools to assess for ASD. Among these measurements, the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS) are considered the "gold standards" for assessing autistic children. The ADI-R is a semi-structured parent interview that probes for symptoms of autism by evaluating a child's current behavior and developmental history. The ADOS is a semistructured interactive evaluation of ASD symptoms that is used to measure social and communication abilities by eliciting several opportunities (or "presses") for spontaneous behaviors (e.g., eye contact) in standardized context. Various other questionnaires (e.g., The Childhood Autism Rating Scale, Autism Treatment Evaluation Checklist) and tests of cognitive functioning (e.g., The Peabody Picture Vocabulary Test) are typically included in an ASD assessment battery.
caption: Process for screening and diagnosing Autism Spectrum Disorder; ASD – Autism Spectrum Disorder; M-CHAT – Modified Checklist for Autism in Toddlers; (+) – positive test result; (-) – negative test result
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