What is Autism? The Basics of Autism Spectrum Condition

Autism spectrum condition (ASC) is a neurodevelopmental condition that means that autistic people have different brains than allistic people.

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Feb 21, 2019

Tiimo member

February 21, 2019
Anna Fay Hermandson
Writer, Lead on partnerships & Community outreach

Quick facts ⬇️

  • ASC is a brain difference that impacts brain anatomy, functioning, and connectivity, which taken together, inform how autistic people experience the world. It is not an illness.
  • People on the autistic spectrum have the same range of intellectual functioning and language abilities as allistic people.
  • It is estimated that 1 out of 160 children has an autistic spectrum disorder, though recent studies report a significantly higher number.
  • At least a quarter of autistic children go undiagnosed. New research actually suggests that this number is higher and many people go undiagnosed through adulthood.

What is autism?

Autism spectrum condition (ASC) is a neurodevelopmental condition. ASC affects brain anatomy, functioning, and connectivity throughout the lives of autistic people. Autistic people have different brains than neurotypical people, meaning that they experience the world differently.

People on the autism spectrum are extremely diverse and, despite stereotyped and oversimplified media representations, have the same range of intellectual functioning and language abilities as allistic (non-autistic) people. Autistic people often have differences from allistic people in terms of communication, sensory processing, executive function, motor skills and coordination, and differences in social interactions. The neurodiversity model asserts these differences in the context of their importance: ‘(w)hereas the deficit model portrays autistic people as ill, broken, and in need of fixing, the neurodiversity perspective portrays it as a form of human diversity with associated strengths and difficulties’ (Robertson 2010).

Often, autistic traits first present during the developmental period, typically in early childhood (1). It is estimated that 1 out of 160 children is on the autistic spectrum, though recent studies suggest a higher number (4). Boys are four times more likely to be diagnosed with ASC than girls (2). This imbalance is likely related to both biological differences, as well as under- or mis-recognition of autism in women and girls, due to gendered social norms, like those that impact masking, and biases in autism research.

Until recently, experts talked about different types of autism, such as Aspergers, Pervasive developmental disorder (PDD-NOS) and autistic condition. With the new ICD-11, the different types have been gathered under the term “autism spectrum disorders”. Many people in the autistic community prefer using autistic spectrum condition or Autistic, to communicate the reality that autism is not an illness; but instead a difference in brain structure and thus, identity and experience. This is why we’ve also chosen to use ASC, identity-first language, and the neurodiversity paradigm.

'Autism is a developmental disability that affects how we experience the world around us. Autistic people are an important part of the world. Autism is a normal part of life, and makes us who we are.’

Causes of autism

ASC is a heritable condition. Genes inherited from one or both parents can impact the development of an autistic brain. The particular way that genetics impact the development of an autistic brain is not well understood (3) and certain environmental conditions probably impact the formation of an autistic brain. Diversity has always been important to human survival, and neurodiversity - the diversity in people’s neurotypes and the consequent diverse ways of seeing the world - is a key part of this. As the Autistic Self Advocacy Network writes ‘Autism is a developmental disability that affects how we experience the world around us. Autistic people are an important part of the world. Autism is a normal part of life, and makes us who we are.'



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How is Autism diagnosed?

It isn’t easy to diagnose ASC, though the diagnosis process varies significantly depending on age and healthcare system. However, the process is usually based on a combination of observations and clinical interviews that assess different factors like communication, social interaction, and repetitive behaviours and/or interests. Due to long waits for diagnosis, as well as systemic racist, sexist and ageist bias in diagnostic processes, more and more autistic people are choosing to self-diagnosis and then find online and in-person communities and seek out peer support and other support strategies that way.

Support for Autistic people

Though autism is diagnosed, ASC is a brain difference not an illness. Autism acceptance - of oneself and by one’s community - is so important that it has been shown to be a significant protective factor in mental health, particularly depression (7).

Certain therapies, like CBT, music therapy, animal therapy, as well as counselling and/or coaching, can be supportive for some people on the autism spectrum. Alternative communication methodologies (like PECS, sign language etc.) can support autistic people’s quality of life by enabling them to self-advocate. Routines play an important role in the daily lives of many autistic people and can help reduce anxiety and improve sleep quality (this applies for allistic people as well). Assistive technology tools, sensory tools, and/or other physical accommodations can also be important.

Researchers and advocates have encouraged a shift from a focus on autistic traits to quality of life. Even relying on existing quality of life indicators comes with certain limitations. There have been some attempts to develop a quality of life measurement specific for people on the spectrum (8). In one study that attempted to develop an index, some examples of things that had either improved quality of life for participants or participants believed would improve their quality of life were environmental factors like stable housing and a switch from full-time to part time work (8). Kapp (2018) suggests that ‘effective social support and subjective well-being mediate whether autistic people achieve a high quality of life.’ (9)

It is increasingly accepted that challenges that many autistic people face are caused and/or exacerbated by the conditions of our society that is not built around the needs of autistic people - like the lack of understanding (both interpersonally and institutionally) about the needs of autistic people and the problematic (and sometimes downright harmful) therapy options. Accommodations are changes in an autistic persons’ environment that mean a person's access needs are met.

Autistic people are an incredibly diverse group (remember the spectrum is more like a pentagonal colour wheel than a spectrum - see this incredible comic by Rebecca Burgess that tries to illustrate how multi-faceted the spectrum really is!), so if you’re supporting someone who’s autistic, ask them!, or if you’re autistic and looking for different support tools or therapies, check out the Autistic Self Advocacy Network or Spectrum News.


  1. ICD-11 for Mortality and Morbidity Statistics, World Health Organization. Retrieved from https://icd.who.int/browse11/l-m/en#/http://id.who.int/icd/entity/437815624.
  2. Baron-Cohen, S. (2017). The Genetics of Autism, Autism Research Centre. Retrieved from http://docs.autismresearchcentre.com/papers/2017_Warrier_The-Genetics-of-Autism.pdf.
  3. Ecker, C., Bookheimer, S.Y. and Murphy, D.G.M., (2015). Neuroimaging in autism spectrum disorder: brain structure and function across the lifespan. The Lancet Neurology, 14(11), 1121-1134. https://doi.org/10.1016/s1474-4422(15)00050-2.
  4. Questions and answers about autism spectrum disorders (ASD), World Health Organization. Retrieved from https://www.who.int/features/qa/85/en/. Symptoms Autism, nhs.uk, https://www.nhs.uk/conditions/autism/symptoms/.
  5. Soke G.N. et al. J. Autism Dev. Disord. 48, 2663-2676 (2018)
  6. Jaarsma, P. (2014). Reflections on Autism: Ethical Perspectives on Autism Spectrum Disorder in Health Care and Education. Linköping Studies in Arts and Science no. 606. Retrieved from https://www.diva-portal.org/smash/get/diva2:696956/FULLTEXT01.pdf.
  7. Cage E, Di Monaco J, Newell V. Experiences of Autism Acceptance and Mental Health in Autistic Adults. J Autism Dev Disord. 2018;48(2):473‐484. doi:10.1007/s10803-017-3342-7
  8. McConachie H, Mason D, Parr JR, Garland D, Wilson C, Rodgers J. Enhancing the Validity of a Quality of Life Measure for Autistic People. J Autism Dev Disord. 2018 May;48(5):1596-1611.
  9. Kapp, Steven K. Social Support, Well-being, and Quality of Life Among Individuals on the Autism Spectrum. Pediatrics Apr 2018, 141 (Supplement 4) S362-S368;

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