7.1.7, 7.1.9 - Autism explanations and support

Features and development

Autism is a developmental condition with varied combinations of characteristics, abilities and support needs.

A child may find conversational turn taking or interpreting an implied meaning difficult. Another may speak fluently but find a sudden change of plan distressing. Repetitive movements, highly focused interests, preference for predictable routines, and heightened or reduced responses to sound, texture or light may occur. These features differ between people and contexts. One behaviour, such as avoiding eye contact, does not diagnose autism. NICE features guidance.

Development is not simply delayed in every area. A child can have an uneven profile, with strong knowledge in an interest and difficulty with everyday communication or organisation. Language and intellectual ability vary; autism should not be equated with an intellectual disability. Some needs become more noticeable when school or social demands increase. Supportive settings can make participation easier, so an observed difficulty reflects the interaction between the child and the environment as well as the child's characteristics.

Autistic children can form attachments and care about other people. Difficulty expressing or interpreting a message is not proof of absence of affection or empathy. A child who covers their ears in a noisy room may be managing sensory overload rather than refusing to cooperate. Explanations should help us ask what the child experiences and what support would help. They should not blame parents or make a classroom exercise into diagnosis.

Genetic explanation

The genetic account explains autism partly through inherited and newly arising genetic variation influencing neurodevelopment.

Genes influence processes by which nerve cells develop, connect and communicate. Many variants can contribute to a person's likelihood of autism; there is no single gene that explains all autistic people. Some variants are common and each has a small association with likelihood, while some rarer variants can have larger effects. A variant may be inherited, or arise newly, so the absence of a diagnosed autistic parent does not disprove a genetic contribution. Research on genetic variation supports contributions from multiple variants. Research connecting risk genes with neuronal development also shows different molecular routes rather than one universal defect. Original genetic-variation research, original neuronal-development research.

Twin evidence offers a test of genetic involvement. Monozygotic twins share almost all their genetic sequence, whereas dizygotic twins share on average about half their segregating genetic variants. Higher similarity for autism in monozygotic than dizygotic pairs is consistent with genetic influence. Tick and colleagues' (2016) meta-analysis reported substantial heritability estimates, ranging from 64% to 91% across its analyses. Heritability describes the proportion of variation in liability associated with genetic differences in the populations and models studied. It does not mean that a particular child is “91% genetic”, nor that autism is inevitable or support cannot help. Original meta-analysis record.

Twin comparisons do not isolate inheritance perfectly. Monozygotic twins can share more similar experiences, ascertainment and diagnostic definitions vary, and estimates depend on statistical assumptions. Genetic associations alone do not demonstrate every step from a variant to a characteristic. The account is strong evidence against explanations that attribute autism to cold parenting, but it does not establish that every individual has the same biological pathway. Genetic influence on development and environmental influence on wellbeing can coexist.

Theory-of-mind explanation

The cognitive account asks whether difficulty representing another person's mental state can explain some social-communication difficulties.