Broader Autism Phenotype (BAP) & Autism Spectrum Disorder (ASD)

Broader Autism Phenotype (BAP) is a term used to describe mild, subclinical traits and characteristics of autism found in some individuals in the general population that are not significant enough to warrant a diagnosis of Autism Spectrum Disorder (ASD). While BAP can be considered a normal variation of human behaviour and cognition¹, ASD represents a more pronounced and clinically problematic manifestation of these traits. Research shows a greater prevalence of BAP in family members of individuals with ASD compared to families with no history of ASD, reflecting the largely heritable nature of autism². The following points can help us better understand the distinction between BAP and ASD.

Important Note: While “Autism Spectrum Disorder” (ASD) is a formal diagnostic term, “Broader Autism Phenotype” (BAP) is not. The latter is a scientific description of the mild, subclinical autistic characteristics found in some individuals in the general population. Individuals with BAP generally do not require intervention from a clinician regarding their autism-like presentation.

1. ‘Autism Spectrum Disorder’ is a Diagnostic Construct: There isn’t a natural divide between BAP and ASD^3,4; one just gradually merges into the other within the population. For this reason, Criterion D of DSM-5-TR diagnostic criteria for ‘Autism Spectrum Disorder’ stipulates that a diagnosis of ASD should only be made when an individual’s autistic “symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning”⁵. (The professional carrying out the diagnostic assessment will typically use a standardised measure of adaptive functioning to help determine whether the day-to-day challenges experienced by the individual are clinically significant). Thus, ASD is essentially a diagnostic construct used by psychologists and physicians (psychiatrists, paediatricians etc.) to distinguish individuals with clinically problematic autism presentations from those with milder, subclinical presentations.
2. Cognitive Strengths Associated with Autism: It is sometimes pointed out that certain cognitive strengths, such as an eye for detail, enhanced pattern recognition, or good systemising ability are found in some individuals on the autism spectrum. However, it is important to note that the said strengths are not exclusively found in individuals who meet the diagnostic criteria for ASD; they are also found in people with subclinical BAP presentations, as well as in some individuals who have no discernible autistic traits/characteristics. (It is also important to emphasise that many individuals with BAP/ASD do not actually show any of the mentioned cognitive strengths).
3. Purpose of an ASD Diagnosis: The ASD diagnostic label helps identify individuals whose autistic presentation is problematic enough that they warrant intervention from a clinician, learning support, a placement in a special school, and/or home supports or benefits such as domiciliary care allowance etc. Through the assessment process, clinicians will usually obtain a detailed profile of the individual’s personal strengths and needs. This is beneficial from the perspective of tailoring appropriate, personalised intervention plans, and also (in the case of adults with ASD) helping the client obtain employment suitable to their unique skill set. Nevertheless, it must be remembered that individuals with ASD attend a clinician because of their various difficulties and challenges in areas such as interpersonal interactions, making friends, communication skills, multi-tasking etc., and this is ultimately what they seek intervention for.

In summary, BAP and ASD both form part of the same broad continuum of autistic traits/characteristics, but they are conceptually distinct. The latter is diagnosed by clinicians when the individual’s autistic presentation causes them significant difficulties in important areas of day-to-day functioning. In this sense, ASD is, by definition, a disorder. Understanding the distinction between BAP and ASD and recognising the diversity of strengths and challenges of those on the autism spectrum helps us better support individuals and families affected by ASD.

– The Autism Hub Team, 29/07/2024

References

1. Landry, O. & Chouinard, P. A. (2016). Why we should study the broader autism phenotype in typically developing populations. Journal of Cognition and Development, 17(4), 584–595. doi: 10.1080/15248372.2016.1200046
2. Rubenstein, E. & Chawla, D. (2018). Broader autism phenotype in parents of children with autism: A systematic review of percentage estimates. Journal of Child and Family Studies, 27(6), 1705-1720. doi: 10.1007/s10826-018-1026-3
3. Kamio, Y., Inada, N., Moriwaki, A., Kuroda. M., Koyama, T., Tsujii, H., et al. (2013). Quantitative autistic traits ascertained in a national survey of 22529 Japanese schoolchildren. Acta Psychiatrica Scandinavica, 128, 45–53. doi: 10.1111/acps.12034
4. Robinson, E. B., Koenen, K. C., McCormick, M. C., Munir, K., Hallett, V., Happé, F., Plomin, R., & Ronald, A. (2011). Evidence that autistic traits show the same etiology in the general population and at the quantitative extremes (5%, 2.5%, and 1%). Archives Of General Psychiatry, 68(11), 1113-1121. doi: 10.1001/archgenpsychiatry.2011.119
5. American Psychiatric Association (2022). Diagnostic and statistical manual of mental disorders, fifth edition, text revision. Arlington, VA: American Psychiatric Association.

Author: autismhub