Thursday, April 23, 2009

New Scientist - Anorexia linked to 'autistic' thinking

Very interesting article - if this is true, it could provide some much needed new tools for working with anorexia, one of the most challenging disorders to "heal." And understanding the mechanisms at work can also help to develop future tools for therapy.

Anorexia linked to 'autistic' thinking

A GROWING appreciation of the links between anorexia and autism spectrum disorders has uncovered new opportunities for treating the eating disorder.

Mental health professionals are now attempting to train the brains of people with anorexia to be more flexible and to see the big picture as well as fine details. In doing so, they hope patients will be less inclined to obsess about body weight and calories and be better equipped to overcome their eating disorder in the long term, as well as gaining weight more immediately.

Last month, the international Academy for Eating Disorders published a paper calling for eating disorders (EDs) such as anorexia and bulimia to receive the same degree of healthcare as other biologically based mental illnesses such as schizophrenia, bipolar disorder and obsessive compulsive disorder (OCD) (International Journal of Eating Disorders, DOI: 10.1002/eat.20589). Other groups are even calling for anorexia to be placed in the same diagnostic category as autism spectrum disorders (ASD).

The main reason for this change is a growing understanding of the biological basis of EDs. Twin studies suggest that between 50 and 83 per cent of EDs have a genetic basis. Now, evidence suggests that people with anorexia have cognitive traits associated with ASD. "Eating disorders and autism spectrum disorders are obviously not the same thing, but they do have some things in common," says Janet Treasure of the Institute of Psychiatry in London.

Treasure had already discovered that anorexia was associated with extreme attention to detail and a rigid, inflexible style of thinking - traits also associated with ASD.

To investigate further, her team used neuropsychological tests to measure central coherence, or the ability to see the big picture as well as the finer details, in 42 women with anorexia and 42 without it. Women with anorexia had weaker central coherence, with a bias towards local, rather than global processing (International Journal of Eating Disorders, vol 41, p 143).

In a separate study, Treasure and her colleagues found that 45 per cent of people with anorexia or bulimia have problems "set-shifting", or modifying their behaviour in response to changing goals, compared to just 10 per cent of healthy people.

This type of focused thinking can be a beneficial skill, but when thinking becomes obsessive, for example, it can be destructive, says Treasure, who presented her results at a meeting of the British Psychological Society in Brighton, earlier this month.

In another series of studies, Treasure's team, together with Kate Tchanturia, also of the Institute of Psychiatry, assessed empathy, systemising ability, and other traits on the autistic spectrum in 22 women with anorexia and 45 without it. They found that although those with the eating disorder didn't differ from healthy women in terms of empathising or systemising, they did show elevated scores on other autistic traits like poorer social skills, and greater attention to detail (British Journal of Clinical Psychology, DOI: 10.1348/014466507x272475).

Simon Baron-Cohen of the Autism Research Centre in Cambridge, UK, is also measuring whether adolescents with anorexia score higher on autistic traits than healthy people, as he suspects that some of them may actually have undiagnosed Asperger's syndrome. "We have always known that Asperger's syndrome was diagnosed more often in males," he says. "The new question is whether it takes a different form in females, and can account for at least a subgroup of those who are diagnosed with anorexia."

If it does, this could have important implications for the way that anorexia is treated. "As well as treating the 'eating disorder' the clinician and the patient might [also] focus on social skills," says Baron-Cohen, although he adds that weight gain would remain a key target.

Tchanturia is already conducting a study in around 30 people with anorexia, who are having cognitive remediation therapy (CRT) to encourage flexible and bigger-picture thinking. For example, patients are given an exercise in which they have to summarise several pages of text, to practice seeing the gist rather than the details. "We're putting the focus on how people think, rather than what people think," says Tchanturia.

The technique has already had some success - in a pilot study of 19 patients with anorexia, 17 patients said they felt it helped them to think more flexibly - although it's too early to say whether it will help their anorexia in the long-term. "They found the treatment helpful in reducing their perfectionist tendencies and it helped them to see things more holistically," Tchanturia says (International Journal of Eating Disorders, DOI: 10.1002/eat.20536).

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