The Neuroscience of Anxiety & Anorexia

Think back to the last time you experienced feeling “hangry”—irritable, cranky or uncomfortable due to hunger. Perhaps it was when you had gone too long between meals, got held up in a lunch meeting or were engaging in a restrictive diet plan. This uncomfortable and desperate feeling occurs when we are depleted, and our bodies need energy.  Interestingly, for an individual struggling with anorexia, the experience of being overly hungry is quite different. Emptiness and energy depletion can actually leave an individual with anorexia feeling better. To understand this phenomenon, renowned researcher Walter Kaye has collaborated with a number of scientists to further understand the neuroscience behind these paradoxical experiences.

When Walter Kaye began his research in the 1980’s, he noted being “struck by how homogenous the symptoms [of anorexia] were.” Kaye disagreed with the stance of many medical professionals at the time, who felt that anorexics were selfish, vain, willful, even “petulant teenagers” that simply needed to choose to get better. He recognized early on that something in their biology was causing anorexia and that by identifying underlying biological causes, more informed treatments could be developed. For those suffering with anorexia nervosa, a greater understanding of the neurological processes driving their experiences has helped many to reduce the blame they place on themselves and challenge stigmas associated with the disease. One such individual, “Heather,” who shared her experience in a recent The Atlantic article, recalls the first time the neuroscience of anxiety and anorexia was demonstrated to her in a treatment program. She writes, “I realized I wasn’t completely crazy…It was a huge relief. It is real and I’m not making it up and I’m not a complete loser.”

By debunking the myth that anorexia is a matter of personality or willfulness and evaluating the various neurological practices at play, we can address this disease with greater compassion and understanding.

Cerebrospinal Fluid:

Dr. Walter Kaye has found that women with a predisposition to anorexia had indicators in their level of cerebrospinal fluid. These individuals had an unusually high level of neurotransmitter serotonin in the cerebrospinal fluid. While we often think of serotonin as a “feel-good neurotransmitter,” too little serotonin is linked to depression and too much serotonin is linked to a chronic state of anxiety and irritability. Three quarters of those diagnosed with anorexia have been known to suffer with anxiety, social anxiety or OCD and related diagnoses prior to their anorexia diagnosis. Kaye believes that this flooding of serotonin makes certain individuals more vulnerable to anorexia.

Serotonin & Tryptophan:

Tryptophan, an amino acid often discussed around the Thanksgiving table, is necessary in the synthesis of serotonin. When you eat less food, your tryptophan levels decrease and thus reduce your body’s serotonin levels. For those individuals with a predisposition to anorexia, starvation will directly reduce the amount of tryptophan and serotonin in the brain, thus reducing anxiety, partially explaining the lack of anxious or ‘hangry’ responses to lower caloric intake. The problem here? The brain will retaliate. Over time, starvation will result in the development of more receptors for serotonin, as the brain tries to “wring out” as much serotonin as possible. This increased sensitivity to serotonin will result in more irritability and anxiety so when eating does occur, there will be a surge of serotonin that results in panic, instability and even rage. The brain has now become hypersensitive and this negative feedback loop has “locked itself into place.” Eating becomes synonymous with anxiety and discomfort.

Motivation & Reward:

Researcher Walter Kaye shares “One reason that people with anorexia are able to starve themselves is that when they get hungry, the parts of the brain that should be driving reward and motivation just aren’t getting activated.” A study researching the brains of women who had recovered from anorexia, discovered that the brain responded less intensely to sugar water than to their healthy control counterparts. These individuals were noted to find sweets less rewarding even when hungry and disinterested in food even when highly palatable food is plentiful. That experience of “yum!” when you bite into a rich piece of chocolate or cake, does not happen for the anorexic brain. The reward area of the brain is quiet while the fear response remains on overdrive. Through fMRI research, Kaye found that “Unlike most people, whose brains respond strongly to rewarding things such as sweets, people with anorexia are generally far more sensitive to punishment (the removal of something pleasant) than reward.”

With greater understanding of these mechanisms, individuals in eating disorder treatment programs are better able to succeed at recovery. Families and loved ones also report feeling a greater sense of compassion after learning about this biologically based brain disorder. As a community, we can do our part to reduce stigmas, prevent invalidating statements such as “just eat!” or “just gain some weight!” and begin to tell our loved ones, “I finally get it!”

Know someone who is suffering from anorexia? Reach out to us at Columbus Park to learn more about our treatment center and gold-standard interventions.


Arnold, C.  (2016. March 30) The Challenge of Treating Anorexia in Adults.  Retrieved from