Autism Diagnostic Assessment 

aboutASD
ASSESSMENT

Misdiagnosis is common.

Research tells us that many autistic individuals experience misdiagnosis prior to being diagnosed with ASD, especially women for whom symptomatology of ASD is less recognized (Dell’Osso & Carpita, 2023).

Prior to receiving an ASD diagnosis, individuals are often diagnosed with conditions that are frequently comorbid or resemble some characteristics of ASD, such as: obsessive compulsive disorder (OCD) or another anxiety disorder, borderline personality disorder (BPD), anorexia nervosa, or attention deficit hyperactivity disorder (ADHD), to name a few.

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Meeting diagnostic criteria.

Essentially, an ASD diagnostic process includes investigating whether an individual meets the diagnosis criteria for ASD (as outlined in the most recent Diagnostic and Statistical Manual of Mental Disorders (published by the American Psychiatric Association) or in The World Health Organization’s International Classification of Diseases, 10th Edition). The diagnostic criteria for ASD include a dyad of social communication and restrictive and repetitive patterns of behavior, that are further broken down into finer categories within the DSM. The DSM-5 criteria also includes a rating of severity of symptoms and an acknowledgement of the impact of atypical sensory processing. The autistic characteristics have to be present in the early developmental period of an individual.

The diagnostic process relies on a clinician’s “best estimate clinical judgement based on behavioral presentation of the individual in the context of their developmental and medical history,” as autism does not have identified biological markers as yet (Whitehouse et al., 2018).

Assessments.

Clinicians make use of standardized assessments for initial screening and to support their investigation into how an individual’s behavior aligns with the diagnostic criteria. Some examples include the Autism Diagnosis Interview – Revised (ADI-R), Autism Diagnostic Observation Schedule (ADOS), Autism Rating Scale (CARS), or Gilliam Autism Rating Scale – Second Edition (GARS-2).

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Additional information.

In addition to the above assessments, other information collected during a diagnostic assessment (as recommended by the National Guideline for the Assessment and Diagnosis of Autism Spectrum Disorders in Australia) includes: an individual’s medical and health history, family history, languages used, developmental and educational history, functioning abilities (in a variety of settings), goals and strengths, environmental facilitators and barriers, and observed and expressed support needs. Clinicians additionally review existing assessments and make observations of an individual in a multitude of settings (or collect information about an individual’s functioning in various contexts) including informal observation during the assessment process.

The National Guideline for the Assessment and Diagnosis of ASD highlights the importance of identifying “strengths, skills, interests, resources and support systems of an individual and their support network” in addition to identifying an individual’s challenges (Whitehouse et al., 2018). It stresses the importance of a person-centred and family-centred approach, acknowledging the family’s unique insight into the needs and strengths of the family unit.

In addition to establishing whether an individual meets the criteria for ASD, an additional assessment goal is to identify and prioritize support needs and goals, including recommending appropriate follow up services.

An investigation that includes functional assessment by a team of allied health professionals is considered best practice for diagnosing ASD.

Finally, it is advisable to appreciate that oftentimes the language used in the assessment process is reflective of the medical model and terminology of disorder and may not represent alternative perspectives around the meaning of being autistic.

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References:

1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5. Washington, DC American Psychiatric Association; 2013.

2. Dell’Osso, L., & Carpita, B. (2023). What misdiagnoses do women with autism spectrum disorder receive in the DSM-5? CNS Spectrums, 28(3), 269-270. doi:10.1017/S1092852922000037

3. Giacomo, V. & Volkmar, F.R. 2020, "Review: National Guideline for the Assessment and Diagnosis of Autism Spectrum Disorders in Australia (Whitehouse, Evans et al. 2018)", Journal of Autism and Developmental Disorders, vol. 50, no. 6, pp. 2252-2254.

4. Kawa S, Giordano J. (2012). A brief historicity of the Diagnostic and Statistical Manual of Mental Disorders: issues and implications for the future of psychiatric canon and practice. Philos Ethics Humanit Med, 13, 7─2. https://doi: 10.1186/1747-5341-7-2

5. Lai, M.-C., Baron-Cohen, S., & Buxbaum, J. D. (2015). Understanding autism in the light of sex/gender. Molecular Autism, 6(1), 24–24. https://doi.org/10.1186/s13229-015-0021-4

6. Vivanti, G., & Volkmar, F. R. (2020). Review: National Guideline for the Assessment and Diagnosis of Autism Spectrum Disorders in Australia (Whitehouse, Evans et al. 2018) [Review of Review: National Guideline for the Assessment and Diagnosis of Autism Spectrum Disorders in Australia (Whitehouse, Evans et al. 2018)]. Journal of Autism and Developmental Disorders, 50(6), 2252–2254. Springer US. https://doi.org/10.1007/s10803-019-03937-x

7. Whitehouse AJO, Evans K, Eapen V, Wray J. A national guideline for the assessment and diagnosis of autism spectrum disorders in Australia. Cooperative Research Centre for Living with Autism, Brisbane, 2018.