Eating disorders are biological illnesses of the brain

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I recently engaged with fellow eating disorder treatment providers in an online discussion about the biological basis of anorexia nervosa. I want to share parts of that discussion and my views on it with you because I think it is essential for parents, patients and providers to acknowledge the current state of the science of eating disorder treatment, especially when it challenges certain cherished beliefs about the origin of anorexia nervosa and the best course treatment available for it.  Understanding the biological basis for mental disorders helps de-stigmatize them and, importantly, puts a stop to blaming parents for their child’s condition.

By now it is widely understood within the scientific community that anorexia nervosa is a heritable brain disorder. So, gone are the days when patients suffering from this illness faced guilt and social stigma, blamed for “choosing” the behaviors that characterize anorexia, right? Well, apparently not quite. While the science is unequivocal, some providers’ opinions (and practices) are still resistant to change. But I’m afraid the jury is no longer out on this one. It’s the brain, folks, and that’s all.

While this is apparently still difficult for some to accept, parents and patients need to understand this, and seek treatment at eating disorder facilities where providers demonstrate a thorough understanding of it too. In this, thankfully, Kartini Clinic is no longer alone.

The discussion I mentioned started with a couple of questions from a well known psychotherapist (and owner of several residential treatment facilities in California and Oregon):
– If there are behavioral components to an illness how can it be described purely as a “biological disease”?
– If someone chooses to do certain behaviors one day and then the next they don’t, how can this be explained by genetics? After all, everybody knows a person’s genes don’t change from one day to the next.

These are very important questions and ones that I’m sure many parents have asked themselves. But while these would be understandable coming from a lay person, I must admit it is a little discouraging to hear them from an eating disorder professional. For both of these reasons, however, it is essential that they be answered.

Let’s leave aside for the moment the assumption that patients “choose” behaviors and focus on explaining what exactly we mean by “behaviors.”

As the pancreas produces insulin and the thyroid gland produces thyroid hormone, the brain produces behavior.  Behavior is just the visible manifestation of many, many chemical processes in the brain.  Behavior allows us to interact with our environment, including other people. Behavior often appears volitional, when it is more often than not actually steered by unconscious processes and biochemical cascades over which we have little or no control and, by definition, no awareness.  Freud said that.
This is what Eric Kandel, Nobel prize winning psychiatrist and neurobiologist, means when he says: “mind is a range of functions carried out by the brain.”
Human illnesses encompass malfunctioning of or harm to any of our organs.  When the organ involved is the brain, we get derangements in behavior as the endpoint of derangements in certain molecular processes.  Examples of this would be schizophrenia, autism and anorexia nervosa.
But because we are not describing “on/off” switches here, even when the brain (and hence behavior) is profoundly affected or compromised by one of these illnesses, the rest of the brain may function well or even very well.  So, sticking to our area of interest, people with anorexia nervosa may make many decisions that have nothing to do with food or weight or shape, very well.  They may be brilliant in their jobs (also true for some people with autism or schizophrenia).  And, of course, because we do not like to think that (bad) things happen to us randomly or undeservedly, our brains are powerfully programmed to try and make sense of nonsense.  We prefer to think we choose things, such as mental illnesses, because we like to think we can un-choose them.  It makes us feel in control of our fate.
How we explain human illness, our paradigm, if you like, has shifted with the ages.  Hence the comparison I frequently make to old beliefs about such seemingly unrelated illnesses like leprosy, once a common human disease. Leprosy offers us a perfect example of “paradigm shift”.  When there was no understanding of biology or infectious diseases and when the focus of life and education was religion and God, the explanations for many human maladies were taken from this familiar sphere.  People—an entire society– thought leprosy was a punishment for bad or sinful behavior.  People preferred this explanation to one where anyone could get such a terrible disease no matter how virtuous they were.  The point is, the comparison to leprosy is not about leprosy itself, but rather, is an example where the prevailing explanation for the cause of a disease can be widely accepted by most people and still be dead wrong.
As for the question this same writer posed to me: “why offer CBT or any other psychological interventions if AN is a brain disorder”, again, here is Dr. Kandel:

“Insofar as psychotherapy or counseling is effective and produces long-term changes in behavior, it presumably does so through learning, by producing changes in gene expression that alter the strength of synaptic connections and structural changes that alter the anatomical pattern of interconnections between nerve cells of the brain. As the resolution of brain imaging increases, it should eventually permit quantitative evaluation of the outcome of psychotherapy. “

It is not that genes change from one day to the next, but rather that gene expression can be affected by learning.  To quote Dr. Kandel again:

“Genes and their protein products are important determinants of the pattern of interconnections between neurons in the brain and the details of their functioning. Genes, and specifically combinations of genes, therefore exert a significant control over behavior. As a corollary, one component contributing to the development of major mental illnesses is genetic… Altered genes do not, by themselves, explain all of the variance of a given major mental illness. Social or developmental factors also contribute very importantly. Just as combinations of genes contribute to behavior, including social behavior, so can behavior and social factors exert actions on the brain by feeding back upon it to modify the expression of genes and thus the function of nerve cells. Learning, including learning that results in dysfunctional behavior, produces alterations in gene expression. Thus all of “nurture” is ultimately expressed as “nature.””
These concepts from a “molecular biology of cognition”, which affect—or should affect–how we provide treatment, can be read about in detail in the American Journal of Psychiatry 155:457-469, April 1998  “A New Intellectual Framework for Psychiatry” by Eric Kandel M.D.