Food, it seems, is everywhere now. Yet about 1% of the population has anorexia nervosa, and is starving in the midst of plenty. The question that sufferers, family members, psychologists, and researchers have been trying to answer is why. Why don't anorexics just eat? Most "normal" starving people scarf up any food they can find. Those with anorexia typically don't. They continue to starve themselves. It's baffling, and no one knew exactly why.
In the Middle Ages, the mysterious "starving saints" were thought to be divinely or demonically possessed. Clearly, this kind of starvation required supernatural assistance. In the Victorian Era, the medical profession considered people with anorexia hysterical and stuabborn. More recent psychodynamic therapies postulated family disturbances, or cultural pressures to be thin.
During the last decade or so, researchers have begun looking at biological factors that make someone more likely to develop anorexia, and the factors that keep the disease going after someone initially starts to get sick. Researchers have found that not only do people recovered from anorexia find eating less rewarding, they also find food frankly anxiety-provoking. Pre-illness personality traits like obsessiveness and perfectionism cause people with anorexia to try and be the best they can at eating less and exercising more. People with anorexia also have difficulties with something called set-shifting: their brains seem to get stuck on one thought.
Although research supporting these neuropsychological factors is both intruiguing and supported by a wide range of studies, it might be that anorexia is more than meets the brain. Starvation is an incredibly powerful and profound biological process. It affects every organ in the body, and is one of the reasons anorexia is the most deadly of all psychiatric illnesses. And as researcher Ancel Keys showed in the 1940s, starvation can turn healthy well-adjusted young men into neurotic and psychotic wraiths within a few short months. Donard Dwyer, a psychiatrist at the Louisiana State University Health Sciences Center, published a paper last week in Molecular Psychiatry that lays out a new theory that the fundamental problem in anorexia isn't psychological; it's metabolic. People with anorexia have problems regulating appetite and seeking out food, problems that are triggered by initial bouts of food restriction.
From the paper:
The net result of deficits in the starvation response is that patients fail to exhibit normal appetite or to properly regulate their response to fasting and fuel shortage. This leads to a vicious cycle. Thus, a bias toward denial of food leads to a reduction in calorie consumption, and weight loss. As weight loss proceeds, production of ancillary signals to initiate feeding...is diminished and the starvation response is further activated...The fact that some anorexic patients literally starve themselves to death attests to the failure of evolutionarily conserved survival strategies in AN.
This theory is borne out in what we know about how anorexia begins. Anorexia generally progresses in a stereotypical fashion: anorexia typically starts with a negative energy imbalance. That is, a person burns off more calories than they take in. Sometimes, this negative energy balance is intentional--someone cuts out junk food in order to eat more healthfully, or they increase training for a sport. In other cases, it's not. Someone gets the stomach flu and can't eat for several days, or they experience a massive growth spurt and can't meet their energy needs. For most people, this food restriction is relatively short-lived. But for the small segment of the population that is susceptible to anorexia, the food restriction isn't stopped, and an eating disorder is born.
According to Dwyer and colleagues, people with anorexia don't eat properly not because of deep-seated control issues or because they want to look good in those Size Zero jeans. They don't eat properly because their metabolisms are broken. In the paper's abstract, the authors write "[Anorexia] is primarily a metabolic disorder caused by defective regulation of the starvation response, which leads to ambivalence towards food, decreased food consumption and characteristic psychopathology."
Nor do people with anorexia have insight into the fact that they're starving. Treating anorexia with solely behavioral approaches (ie, encouraging patients to develop insight into their eating behaviors) isn't likely to help what the authors believe is a metabolic disorder. You can't treat diabetes that way, the authors argue, and you can't treat anorexia that way.
"Unless we conceive of it as more of a metabolic function, I don't think we'll get past the first stage of treatment with a lot of the real hard-core patients," Dwyer said in an interview with LiveScience.
This new paper doesn't necessarily invalidate previous studies about psychopathology in anorexia. A broken starvation response can exist alongside problems with perfectionism, OCD, and set-shifting. Further studies will have to be done before anyone knows for sure how valid this new hypothesis is. Regardless of whether new studies support this idea, the research is important on two levels. One, they help emphasize the fact that anorexia isn't a disease and isn't simply chosen or un-chosen. Two, they show just how powerfully starvation affects brain and body. Mental illnesses don't exist separate from the body; they are diseases of the brain, and the brain is part of the body.