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

Summary

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.”The scientists are not advocating for a move towards two diagnostic categories, saying that this could be unhelpful for the many who fall somewhere in the middle.“It is a gradient,” said Warrier. “There are also many other factors that contribute to age of diagnosis, so the moment you go from averages to anything that is applicable to an individual, it’s false equivalency.”The findings come at a time when autism diagnosis has risen steeply, with a nearly 800% increase in diagnoses in the UK between 1998 and 2018. Experts say this is due largely to a widening of the diagnostic criteria and greater recognition of the condition.And, while autism is defined by having challenges with social communication, sensory processing and restrictive behaviours, there is huge variability in how these difficulties present between individuals. Scientists have been looking at whether the population clusters into subgro...