Knowledge base Updated 2 November 2026 2 views

Autism

A lifelong neurodevelopmental difference involving differences in social communication and interaction alongside restricted or repetitive patterns of behaviour, interests or activities, and differences in sensory processing.

Definition

DSM-5 requires persistent differences in social communication and interaction across contexts, plus at least two of: stereotyped or repetitive movements or speech, insistence on sameness, highly restricted fixated interests, and hyper- or hypo-reactivity to sensory input.

DSM-5 merged the previously separate categories — autistic disorder, Asperger's, PDD-NOS — into one spectrum, and added the sensory criterion, which autistic people had been describing for decades before it was formally recognised.

Language is contested and worth getting right. Most autistic adults in English-speaking countries prefer identity-first language (autistic person) over person-first (person with autism); surveys are consistent on this, and many clinical style guides have not caught up.

History

Kanner and Asperger described it independently in the 1940s. The literature spent decades under the influence of the refrigerator-mother hypothesis, which blamed cold parenting, was never supported, and caused enormous harm.

Wakefield's 1998 paper linking MMR vaccination to autism was retracted and its author struck off. The claim has been examined in very large studies repeatedly and there is no link. It continues to cause measurable harm to vaccination rates.

Theory

No single cognitive theory accounts for autism, and the major ones each explain part.

Theory of mind differences: difficulty inferring mental states. Explains some social differences; does not explain sensory or repetitive features, and is complicated by the finding that the difficulty is bidirectional.
Weak central coherence: a processing bias toward detail over gestalt. Reframed as a cognitive style rather than a deficit.
Executive function differences: planning, flexibility, inhibition.
Predictive processing accounts: differences in how strongly prior expectations weight perception, which has the attraction of addressing sensory features directly.

The double empathy problem (Milton) reframes the social difficulty as mutual: autistic and non-autistic people both struggle to read each other, and autistic people communicate effectively with each other. Empirical work supports this, and it undercuts a purely deficit framing.

Research

Prevalence estimates have risen substantially, driven mainly by broadened criteria, better recognition and diagnostic substitution rather than a genuine increase.

Heritability is high, estimated around 70 to 90 percent in twin studies, and hundreds of genetic variants of small effect have been implicated.

Diagnosis is systematically delayed or missed in girls and women, partly because the diagnostic instruments were developed on samples of boys and partly because of camouflaging.

Camouflaging — consciously masking autistic characteristics — is associated with exhaustion, worse mental health and suicidality in several studies.

Applications

Assessment usually combines developmental history with an observational instrument, most commonly ADOS-2 and ADI-R, and neither is sufficient alone.

Support that has evidence targets communication, environment and skills the person wants. Approaches aimed at making autistic people appear less autistic are increasingly criticised by autistic adults, and the evidence on long-term outcomes of intensive behavioural intervention is weaker than its advocacy suggests.

Criticism

The deficit framing is contested by autistic researchers and communities, and the double empathy evidence supports that contestation.
Diagnostic instruments were normed on boys and continue to underdetect girls, adults and people who mask.
Applied behaviour analysis is divisive. Concerns about compliance training and about the outcomes it optimises for are raised most strongly by autistic adults who received it.
Research funding is skewed heavily toward causes and biology over the questions autistic people say matter to them: services, employment, ageing, mental health.
Autistic people are almost absent from the authorship of the literature about them, though this is changing.

References

Milton, D. E. M. (2012). On the ontological status of autism: The double empathy problem. Disability & Society, 27(6), 883-887.
Happé, F., & Frith, U. (2006). The weak coherence account. Journal of Autism and Developmental Disorders, 36(1), 5-25.
Hull, L., et al. (2017). Putting on my best normal: Social camouflaging in adults with autism. Journal of Autism and Developmental Disorders, 47(8), 2519-2534.
Taylor, L. E., Swerdfeger, A. L., & Eslick, G. D. (2014). Vaccines are not associated with autism: A meta-analysis. Vaccine, 32(29), 3623-3629.
Bottema-Beutel, K., et al. (2021). Avoiding ableist language. Autism in Adulthood, 3(1), 18-29.

Written for PsychologyOrbit and reviewed before publishing. It is a summary for professionals and students, not clinical guidance, and it is not a substitute for the primary sources listed above.