Diagnosing Autism

Diagnosing Autism

Diagnosing Autism

Autism is a complex neurological disorder that cannot be diagnosed through medical tests.

Instead, a diagnosis is made based on the presence or absence of certain observable behaviors. Qualified and experienced professionals should perform a comprehensive evaluation to determine the presence of autism symptoms and the impact that these symptoms have on an individual’s life. Because of its complexity, a diagnosis of autism should not be made after a 15 minute exam in a doctor’s office.

Rather, it should only be made after an in-depth assessment process that includes the use of diagnostic instruments specifically determined to be valid for autism, along with observations of the individual in multiple settings. Additionally, because a diagnosis requires symptoms to be present prior to the age of 3, a careful and detailed developmental history should be collected from a parent or caregiver.

To ensure consistency in diagnosis, professionals use standard diagnostic criteria found in the Diagnostic and Statistical Manual – 5th Edition (DSM-V). This manual specifies the required number of symptoms needed in the three core diagnostic areas, which include socialization, communication and repetitive/restricted behaviors and interests. These symptoms must be determined to cause significant impairment in an individual’s life. Finally, the manual requires professionals to ensure that other medical and/or psychological conditions are not present to account for the symptoms.

Who can diagnose autism?

In New York State, autism can only be diagnosed by a licensed psychologist or physician.

Concerns about autism are often first mentioned to a pediatrician at a well-child visit. However, many pediatricians do not have the time or experience needed to make a diagnosis. The New York State Department of Health mandates that all physicians screen for autism at a child’s 9-, 18-, and 24- month visits, even in the absence of parental concerns. A positive screening should result in a referral to a specialized diagnostic clinic. Recommended screening measures include:

  • Checklist for Autism in Toddlers (CHAT) – (2)
  • Modified – Checklist for Autism in Toddlers (M-CHAT) – (3)
  • Pervasive Developmental Disorders Screening Test – (4)

Older individuals may not be referred for a diagnosis until they are in school. Families can consult the Special Education Programs in their school district or with their doctors for information on specialized diagnostic clinics.

Why is ongoing assessment important?

Once a diagnosis is made, it is important to continue the assessment process to ensure that the individual is making progress with any treatments or services they receive.

A lack of progress should prompt revisions to treatment programs or plans. Substantial regressions in skill areas should prompt further medical assessments.

  1. American Psychiatric Association (2013). Diagnostic and statistical manual of mental disorders: Fifth edition DSM-V. Washington, DC: American Psychiatric Association
  2. Baron-Cohen S, Allen J, Gillberg C. Can autism be detected at 18 months? The needle, the haystack, and the CHAT. British Journal of Psychiatry. 1992;161:839–843
  3. Robins D, Fein D, Barton M, Green JA. The Modified- Checklist for Autism in Toddlers (M-CHAT): an initial investigation in the early detection of autism and pervasive developmental disorders. Journal of Autism and Developmental Disorders. 2001;31:131–144.
  4. Siegel B. The Pervasive Developmental Disorders Screening Test II (PDDST-II). San Antonio, TX: Harcourt Assessment; 2004
  5. Lord, C., Rutter, M., DiLavore, P. & Risi, S (1999) Autism Diagnostic Observation Schedule (ADOS). Western Psychological Services
  6. Couteur, Lord, C. & Rutter, M. (2003). Autism Diagnostic Interview-Revised (ADI-R). Western Psychological Services
  7. Schopler E, Reichler RJ, DeVellis RF, Daly K (1980). “Toward objective classification of childhood autism: Childhood Autism Rating Scale (CARS)”. Journal of Autism and Developmental Disorders, 10 (1): 91–103