Anorexia nervosa in women may be caused by autism

Autism, characterised by defects in communication and social interaction, also makes many anorexic patients unresponsive to traditional treatments and may be responsible for anorexia's low recovery rates, according to Professor Christopher Gillberg, of the University of Strathclyde.

Although autism is thought to be a male problem, affecting up to four times more boys than girls, the disorder has been overlooked in women because their autistic traits present themselves differently, according to Prof Gillberg. An obsession with counting calories, for instance, may be an outward sign of autism.

"Our research has shown that a small but important minority of all teenage girls with anorexia nervosa in the general population meet diagnostic criteria for autistic disorder, Asperger syndrome or atypical autism. I've seen quite a number of cases where the anorexia has become completely entrenched because people haven't understood that underlying the eating disorder is autism."

Prof Gillberg said anorexic patients with autism tended to be severe cases because traditional treatment for eating disorders proved ineffective.

For instance, family therapy - a popular psychotherapy in which family members discuss eating with the sufferer - is all but useless for autistic patients.

"If you have an autism spectrum disorder you have great difficulty even understanding basic concepts about other people's thoughts and feelings, which means anything said in a family-therapy session is likely to be misconstrued by the affected individual who will not grasp what is going on in that particular context.

"Instead they need much more concrete, one-to-one interventions."

A spokesman for the Eating Disorder Association welcomed the research and said it could help develop more effective treatments for eating disorders.

About 5 per cent of anorexic patients die from complications of the disorder and only 40 per cent make a full recovery.

Although not addressed in his studies, Prof Gillberg said autism was behind the majority of male anorexia cases. Ten per cent of the 1.1 million reported anorexia cases in the UK are in men.

"My clinical impression over the past 30 years has been that males struck by anorexia nervosa very often - perhaps even in the majority of cases - have autism spectrum disorders," he said.

Judith Gould, director of the National Autistic Society's Diagnostic Centre, agreed with the study's findings.

"We believe we are probably missing autism in girls due to the different way in which it often manifests itself in females. We would also agree that anorexia, which is predominantly diagnosed in girls, could be linked to autism in an unknown proportion of cases."

About 500,000 people in the UK - including 50,000 in Scotland - are thought to have some form of autism.