Autism should not be seen as single condition with one cause, say scientists

"Autism should not be viewed as a single condition with a unified underlying cause, according to scientists who found that those diagnosed early in childhood typically have a distinct genetic profile to those diagnosed later. The international study, based on genetic data from more than 45,000 autistic people in Europe and the US, showed that those diagnosed in early childhood, typically before six years old, were more likely to show behavioural difficulties from early childhood, including problems with social interaction, but remain stable."

"Those diagnosed with autism later, typically after the age of 10, were more likely to experience increasing social and behavioural difficulties during adolescence and also had an increased likelihood of mental health conditions such as depression. The term autism' likely describes multiple conditions, said Dr Varun Warrier, from Cambridge's department of psychiatry, senior author of the research. For the first time, we have found that earlier and later diagnosed autism have different underlying biological and developmental profiles."

Genetic analysis of more than 45,000 autistic people in Europe and the US reveals distinct profiles linked to age of diagnosis. Individuals diagnosed before six years often show early-onset behavioural difficulties, including social interaction problems, that remain stable. Individuals diagnosed after age ten more commonly show worsening social and behavioural difficulties during adolescence and higher rates of mental health conditions such as depression. Autism likely encompasses multiple biological and developmental profiles rather than a single unified cause. Age of diagnosis exists on a gradient, influenced by many factors, and does not map perfectly onto individual cases. Diagnostic rates rose sharply in the UK between 1998 and 2018, driven by broadened criteria and greater recognition.

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