The World Health Organisation estimates that between one and six children in every thousand has an autism spectrum disorder (ASD). This group of neurodevelopmental disorders, characterised by difficulties with social interaction and communication, was recently joined by Asperger syndrome following a change to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). As research into ASDs grows more questions are being raised, such as; why are ASDs seemingly more common in males over females? What role may undiagnosed autistic traits play in other disorders? How will biomarkers and gene testing affect the future diagnosis and treatment of ASDs? Simon Baron-Cohen, leading ASD researcher and co-Editor-in-Chief of Molecular Autism, shares his views on these current issues.
The prevalence of autism has vastly increased over recent decades. What factors do you think have contributed to this trend?
This increase likely reflects better awareness, better screening, more services, a larger number of trained people who can diagnose, and a widening of the diagnostic category of autism to include a ‘spectrum’.
Autism spectrum disorders are thought to be more common in males, although research suggests that females are underdiagnosed. What do you think the real situation is?
In classic autism the sex ratio is four males to every one female. In Asperger Syndrome (AS) it is about nine males to every one female. I suspect this is because many females with AS are ‘under the radar’ and that the true sex ratio in AS is similar to that in classic autism. Why females with AS are undiagnosed is complex, but some suggestions include; that females are better at ‘camouflaging’ their AS, females are more motivated to hide their AS, females with AS may have more cognitive resources to hide their AS (such as better language or imitation skills), and that females with AS may be misdiagnosed more often, for example, with anorexia or borderline personality disorder, or gender identity disorder.
What underlying developmental differences do you think could account for a higher incidence of autism spectrum disorders in males?
Our group has been investigating the role of foetal sex steroid hormones such as testosterone (and its precursors) in the development of autism, and there is growing evidence for this being implicated in autism. The sex steroid hormones are produced in greater quantities in males than in females. Other sex-linked biological factors also include genes, particularly on the X chromosome. The androgenic hormones are also epigenetic, affecting gene expression, so this is not incompatible with a genetic hypothesis.
Has the view of autism changed? How important is it that the media understand the meaning of autism research findings?
The view of autism has shifted over the decades. Before the late nineties we tended to focus on children with classic autism. Nowadays we focus on both children and adults, and not just with classic autism but also Asperger Syndrome. The media has played a role in raising awareness, often through publicising extraordinary individuals such as savants, though it is important that the media does not misrepresent or distort how the whole spectrum is represented, by focusing on savants.
How do you think the search for biomarkers and development of genetic tests will inform diagnosis and treatment of autism in the future?
As we have seen with the remarkable increase in the number of publications to the journal Molecular Autism, there is an explosion of research in this domain. We started the journal just at the right time to provide an outlet for this research. It is too early to speculate about whether or when such research might translate into a biologically based diagnostic test or treatment. Ethically too, we need to be careful that if and when such translation of basic science occurs, diagnostic tests are sensitive and specific enough to be meaningful, and treatments are safe and free of unwanted side effects, and are targeting those symptoms that need treatment, leaving those aspects of autism that do not require treatment free to blossom.
Earlier this year, the American Psychiatric Association released proposed changes to the diagnostic criteria for autism in the DSM-5. What impact will these changes have?
DSM-5 will hopefully improve reliability (agreement) between clinicians/researchers in how they make their diagnosis. In Europe we continue to use the term ‘Asperger Syndrome’ even though this is no longer part of DSM-5, at least until the International Classification of Diseases (ICD-11) is published.
In a recent article in Molecular Autism, you examine whether anorexia and autistic traits are linked. Why is it important to not only consider diagnostic categories but also traits shared across different conditions?
The idea that autistic traits are on a spectrum means that we need to look at people who do not have a formal diagnosis of autism or Asperger Syndrome, but who might still have a higher than average number of autistic traits. People with anorexia are one such group. There are undoubtedly others. These studies will help us make connections between different diagnostic categories and give us clues about the underlying biology of these groups. In the case of the anorexia study, it also suggests new treatment approaches, since focusing just on the eating disorder may be missing other important needs the person has, such as help with social skills or with adapting to change.
As a co-Editor-in-Chief of Molecular Autism, how important do you think Open Access is to autism research?
Open Access is vital if we are to live up to the aspiration that anyone anywhere on the planet may be able to read and use the findings of research (autism-related or other).
What new directions is the field of autism research taking?
I am excited by the acceleration in molecular neurobiological autism research, but it is important that cognitive research is not neglected. Equally, intervention and treatment research is vital if we are to make the lives of people with autism easier, and make the environment more autism-friendly.
What would you say are the biggest challenges remaining?
I would like to see a significant increase in funding for autism research in the UK, since as the recent report from Research Autism (A Future Made Together – Shaping Autism Research, 18 June 2013) suggests, the US spends 18 times more than the UK on autism research, after taking into account population size. This is one big obstacle to progress.
Secondly, I would like to see a significant increase in funding to services for people with autism in the UK, since despite the Autism Act in 2009 and the Autism Strategy in 2010 there are still very few clinics for adults with suspected autism or Asperger Syndrome, and in many parts of the UK there is no post-diagnosis support for adults with a diagnosis of AS. Employment among this group is also unacceptably low, considering that these are intelligent and skilled individuals, and that unemployment contributes to a feeling of marginalization and exclusion, and to secondary and preventable depression. There is much to be optimistic about with the growth of awareness about autism, but no room for complacency.