Genes linked with a greater risk of developing autism may also be associated with higher intelligence, a study suggests.

Researchers have found new evidence linking genetic factors associated with autism to better cognitive ability in people who do not have the condition.

Autism is a developmental disability that can cause significant language and speech difficulties.

Developmental disorder

The relationship between autism and intelligence is not clear, researchers say.

Up to 70 per cent of individuals with autism have an intellectual disability, but some people with the disorder have higher than average non-verbal intelligence, the team says.

Non-verbal intelligence enables people to solve complex problems using visual and hands-on reasoning skills requiring little or no use of language.

As we begin to understand how genetic variants associated with autism impact brain function, we may begin to further understand the nature of autistic intelligence. Dr Toni-Kim Clarke Division of Psychiatry

Cognitive ability

Researchers 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 among people who never develop autism, carrying genetic traits associated with the disorder is, on average, linked to scoring slightly better on cognitive tests.

Intellectual advantage

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.

This study suggests genes for autism may actually confer, on average, a small intellectual advantage in those who carry them, provided they are not affected by autism. Professor Nick Martin Queensland Institute for Medical Research

The study is published in the journal Molecular Psychiatry.

The research was funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorates, Scottish Funding Council, The Wellcome Trust, The Medical Research Council and Age UK.