News roundup

Medical Research Council review sets research agenda for autism

Susan Mayor, London

The Medical Research Council has published a major review of research which reveals that the prevalence of autism is higher than had been thought but indicates no association with the measles, mumps, and rubella vaccination.

The review was commissioned by the Department of Health in March 2001, partly in response to public concerns raised by research alleging that MMR vaccination might be linked to an apparent increase in the numbers of children with autism. It was designed to be a wide ranging review of research into different aspects of autism and other disorders in the autism spectrum, to identify gaps in knowledge and to make recommendations on future research in the United Kingdom.

Three groups of scientists examined the research evidence and assessed the strength of knowledge based on research in epidemiology and case definition; physiology and infection; and psychology and behaviour. For the first time in a research review by the council there was extensive input from the outset from lay people, who put forward questions that reflected the concerns of parents of children with autism.

The report found that autism was more prevalent than had previously been thought: around six in 1000 young children have a disorder in the autism spectrum.

Carol Dezateux, clinical reader in epidemiology at the Institute of Child Health at Great Ormond Street NHS Trust and chairwoman of the review’s epidemiology subgroup, said: "This estimate makes autism spectrum disorders far more common than was previously generally recognised."

Most of the apparent increase was considered by the reviewers to have resulted from changes in case definition, as well as increased awareness of the condition. The reviewers thought it most likely that autism results from several causes, but they argued that the strongest evidence was for a genetic component. They said: "It seems likely that several genes interact to create susceptibility to the disorder. The interplay between genetic and environmental factors is also likely to play a key role but the nature of these interactions is not yet known."

It was concluded that current evidence did not support the link between MMR and autism spectrum disorders.

The review was chaired by Professor Eve Johnstone, who is also chairwoman of the council’s neurosciences and mental health research board. She said, "The report has identified some successes in research into autism but there is still a long way to go to better understand these disorders." She added: "The participation in this review of people with autism, their carers, and people with experience of support groups has enriched both the process and its outputs. Further partnerships which give lay organisations access to scientific expertise and give scientists access to lay perspectives can only be of benefit."

For the future, the report recommends building on the existing strengths of research into autism by improving coordination between different research disciplines and improving research training in service settings. It also called for more research on the definition of autism spectrum disorders, especially in adults, noting that such research is "crucial both for future research and for provision of services" for people with the disorder.

More basic biological research studies were also suggested—an acknowledgement that there is still a lot of uncertainty about the biological processes involved in autism, in the brain as well as other organs. Large population studies were proposed, to address questions about environmental risks and their interaction with genetic factors. The council is now discussing with the Department of Health how to act on these proposals.

Dr Dezateux concluded that progress in autism research would depend on adequate funding.