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Visions Journal

The Vast and Varied Landscape of Autism Spectrum Disorder

Brenda Fossett, PhD, BCBA-D

Reprinted from the The Many Faces of Neurodiversity issue of Visions Journal, 2023, 18 (3), pp. 8-11

Stock photo of woman with children in classroom

The diagnosis of autism spectrum disorder (ASD), sometimes referred to as autism, has existed in various forms since 1943. That’s when Dr. Leo Kanner published a paper in which he described 11 children seen in his office, all of whom displayed similar characteristics. The children appeared to have difficulty relating to people and objects in their environment, were delayed in the use of speech or used speech in unusual ways and showed a strong desire for sameness.1

The next year, German psychiatrist Hans Asperger published his own paper after he identified a group of children who had difficulty making friends and engaging in conversation, but who were often very knowledgeable in their areas of special interest.2

From then on, and for many decades, autism was viewed as a psychiatric condition and diagnosis was left to the discretion of individual clinicians—there were no formal diagnostic criteria. That changed in 1980 when autism was recognized as a developmental disorder. The Diagnostic and Statistical Manual of Mental Disorders-III (DSM-III) included autism in a new category of conditions called Pervasive Developmental Disorders.

Evolving criteria for autism spectrum disorder

The diagnostic criteria for autism have been evolving ever since. Increasingly, these criteria reflect the understanding that autism occurs across the lifespan, not just in young children, and that individuals may be impacted in different ways and to varying degrees.3 The most recent revision of the diagnostic criteria appeared in the DSM-54 in 2013 under the label “autism spectrum disorder.”

The new criteria identify two domains where an individual with ASD experiences differences or challenges:

  1. social communication and social interaction
  2. restricted, repetitive patterns of behaviour, interests or activities

The most recent diagnostic criteria also identify severity at three levels:

  • Level 1: requires support
  • Level 2: requires substantial support
  • Level 3: requires very substantial support

While discussion of the details of diagnostic criteria goes beyond the scope of this article, it’s important to note that there has been a significant widening of criteria over the past several decades.

One of the most useful features of the current diagnosis lies in an aspect of the current label: spectrum. We now understand that people with ASD are part of a highly diverse group. Historically, doctors believed that the majority of people with ASD had some degree of intellectual disability, lacked a desire for social relationships and interaction and were incapable of little beyond very basic skills.

Clinicians and researchers now recognize that a large proportion of those with ASD have average to above-average intelligence, want engagement with and connection to others and are capable of making meaningful contributions to the lives of those around them, their communities and, in many cases, their professions. There are highly skilled and sought-after professionals with ASD, such as the academic Temple Grandin, author John Elder Robison and photographer Stephen Shore.

Just as there are those with high abilities, there are those who are significantly impacted in ways that interfere with the basic activities of daily life. These individuals often struggle to develop communication and language skills; demonstrate difficulty learning basic skills, including those of daily living and self-care; and engage in behaviours that are severely disruptive or harmful. These individuals need intensive support with day-to-day tasks, often throughout their lives.

Strategic support for individual needs

Approaches to support and education can vary. For young children who show significant delays in achieving developmental milestones, access to intensive, early intervention is appropriate and necessary. Interventions can come from the field of applied behaviour analysis (ABA). The main goal of ABA is not to cure ASD or make a person “less autistic;” rather, its purpose is to teach socially important behaviours that lead to improved quality of life for the individual. For young children, interventions like the Early Start Denver Model are now used more often than the structured, adult-directed approaches of the past. The new approaches embed ABA-based interventions into play-based activities that interest the child in order to teach, for example, communication, cognitive or social skills.

Speech-language pathology and occupational or physical therapy can also support young children in reaching developmental milestones. Behaviour analysts, speech-language pathologists and occupational or physical therapists work together to provide services to young children diagnosed with ASD. Other children may meet developmental milestones yet have trouble with specific skill areas or feel anxious during specific activities or in some environments. In these situations, focused interventions designed to address specific needs are more appropriate than intensive, comprehensive interventions. As children enter school, they may need ongoing intervention and additional supports to address academic skill development, social communication or other skill areas.

As youth move towards adulthood, various supports can help individuals to become as independent as possible and build a rewarding, fulfilling life from their perspective. This area has been largely ignored until relatively recently. We now recognize that children with ASD grow to become adults with ASD. Some adults need 24/7, intensive supports. Others may need intermittent or targeted supports to help with things like getting and keeping jobs, dating and relationships, parenting, financial management and so on.

Building trust for ASD wellness

In ABA, which is my field of practice, researchers and practitioners are striving to work more collaboratively with adults with ASD to support them in identifying their own needs and goals. We are designing appropriate supports with their input, involvement and consent, and assisting them in acquiring the skills they need to achieve their desired outcomes. Increasingly, we want to help people with ASD develop self-determination skills early on. That way, they can advocate for their own needs, as much as possible, throughout life.5 This is a particularly exciting aspect of behaviour analytic work today.

While there is much that we currently know about ASD, much is still unknown. We know ASD is genetic, yet we do not fully understand the specific mechanisms at play. We know that people with an ASD diagnosis are diverse, with a wide range of strengths and needs, yet we don’t know why some individuals are able to achieve independent, self-directed lives, while others need more support. Despite developing several evidence-based interventions to support children with ASD, we don’t know which children are most likely to respond best to what intervention, or why.6

There are still many, many questions. What those of us who live and work with people with ASD increasingly recognize is this: all people with ASD have value, can contribute and can learn. When we meet individuals where they are at, respect their interests and desires and apply evidence-based interventions while also listening to their voices, we can establish meaningful relationships built on mutual trust. This trust allows us to serve them in achieving whatever outcomes are best for them.

Related Resources

Below is a list of BC-based resources to learn more about autism spectrum disorder and find support for yourself and loved ones:

  • Autism Community Training (ACT) – visit the following ACT website pages for up-to-date assistance:
  1. upcoming live events (BC and web-streamed):
  2. Autism and Intellectual Disability Search:
  3. BC community resources search:
  4. Autism Videos @ ACT:
About the author

Brenda is a Board Certified Behavior Analyst on faculty at Capilano University. After an early career teaching deaf children with developmental disabilities, she earned her doctorate in special education and now presents widely on ways to support individuals with developmental disabilities. Brenda advocates for the use of diverse strategies to facilitate learning and enhance independence


  1. Kanner, L. (1943). Autistic disturbances of affective contact. Nervous Child. Journal of Psychopathology, Psychotherapy, Mental Hygiene, and Guidance of the Child, 2, 217–250.

  2. Asperger, H. (1944). Autistic psychopathy in childhood. In U. Frith, (Ed.), (1991), Autism and Asperger Syndrome (pp. 37–92). Cambridge University Press.

  3. Rosen, N. E., Lord, C., & Volkmar, F. R. (2021). The diagnosis of autism: From Kanner to DSM-III to DSM-5 and beyond. Journal of Autism and Developmental Disorders, 51, 4253–4270.

  4. American Psychiatric Association (2013). Diagnostic and statistical manual of mental disorders (5th ed., text rev.).

  5. Hanley, G. (2021, September 9). A perspective on today’s ABA. Practical Functional Assessment: Understanding Problem Behavior Prior to its Treatment.

  6. Cerasuolo, M., Simeoli, R., Nappo, R., Gallucci, M., Iovino, L., Frolli, A., & Rega, A., (2022). Examining predictors of different ABA treatments: A systematic review. Behavioral Sciences, 12(8), 267.

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