The relationship between autism and intelligence is not clear, researchers say. Although up to 70 per cent of individuals with autism have an intellectual disability, some people with the disorder have relatively well-preserved, or even higher than average, non-verbal intelligence, the team says.
Autism is a developmental disability that can cause significant language and speech difficulties. Non-verbal intelligence enables people to solve complex problems using visual and hands-on reasoning skills requiring little or no use of language.
Researchers at the Universities of Edinburgh and Queensland analysed almost 10,000 people recruited from the general population of Scotland. Individuals were tested for general cognitive ability and had their DNA analysed.
The team found that even among people who never develop autism, carrying genetic traits associated with the disorder is, on average, linked to scoring slightly better on cognitive tests.
Researchers found further evidence of a link between autism-associated genes and intelligence when they carried out the same tests on 921 adolescents who were part of the Brisbane Adolescent Twin Study.