There are many studies suggesting an overlap between anorexia (AN) and higher functioning autism/Aspergers (AS); others dismiss the idea. What exactly is research showing, and why is this important for treatment?   

At first glance, you’d think AN and AS were significantly different. AS is a developmental disorder, characterized by poor social functioning, cognitive inflexibility and repetitive behavior. AN is an eating disorder characterized by significant weight loss, disturbed eating habits and extreme obsession with the body, often diagnosed later in teenage years. With AS, there’s usually a ratio of more males than females, while AN usually has a higher female to male ratio. Why even think they’re connected?

A current theory according to Mandy and Tschanturia is that AS raises the risk of AN in females, especially since women with anorexia show inflexible thinking, obsessions and limited social relationships. Other studies have found family histories showing both AS and AN, and retrospective reports by parents and the patients themselves have suggested that a significant number of individuals have AS symptoms before they develop AN.

Many research studies have shown that the frequency of women with AN who are diagnosed with AS (or who have have traits typical of AS) is much higher than in the general population. A criticism of these studies is that the AS symptoms could be caused by the impact of starvation on the brain, and that these symptoms could improve significantly when the woman is of normal weight.

Some studies suggest that cognitive inflexibility and other traits of AS persist for those with AN after they return to normal weight. This could be because these individuals have AS; it’s also possible that they have personality traits are similar to AS but not due to autism. For example, inflexibility, attention to detail and trouble shifting focus or behavior could reflect obsessive and perfectionistic traits in AN patients.

If you want to say that people with AS are prone to AN, it’s important to show conclusively that AN women (and men) had AS (or AS traits) before developing eating disorder symptoms. Current evidence for this is based on histories given by the patients and their parents. This evidence has drawbacks; memory can be biased towards finding what one is seeking. It would be important to have information that was collected prior to the eating disorder, such as doctor or school records.

If AS predisposes people to AN, especially with women,  that would be very important to know so parents and doctors could watch for the development of AN symptoms. Since AN is most likely in females, it’s vital to recognize girls and women with AS. Mandy pointed out that women with AS are generally under- diagnosed because they don’t conform to criteria based on a male model. Criteria for diagnosing AS or AS traits in all genders would have to be clearcut for effective research and for appropriate attention by parents and professionals.

Why is all this important? Whether AS and AN are causally connected or not, research does suggest that those who have AN and ongoing AS or AS traits have more resistance to treatment, and therefore can have a less positive outcome. For example, some traditional therapies for AN are behavioral programs and have rigid rules and consequences; my experience is that this approach doesn’t work well  for those with AS. Therefore, it’s important to assess AN patients for AS traits, and to tailor treatment keeping this in mind when working for the most successful outcome.