In 20ll, I authored a book: When Food is Family: A loving guide to heal eating disorders. Among one of the very first professional comments I received on one significant eating disorder professional message board was from a local colleague. The criticism of my book was strong and accusations made that I was turning back the eating disorder clock in terms of understanding etiology. The comments were also divisive, in what felt like at the moment, to further polarize professional discourse by categorically asserting that eating disorders were genetically determined.
Most of the reflections and comments, however, over the course of several weeks on the professional message board were very favorable and challenging of comments that were rigidly and exclusively aligned with a genetic understanding of eating disorders. The majority acknowledged me for taking steps to bridge the schism in the professional field regarding etiology. There were some who maintained a firm stance in stating that eating disorders were not only caused by genes, but that psychology, relationships, upbringing, nurture, environment and culture had little, if anything, to do with causation.
I asserted in more than one Blog Posts on PT my frustration with the schism in my field among professionals in that some were falling prey to the extreme and rigid thinking that we try to correct in our patients—all or nothing beliefs. Eating disorders are neither this nor that, or if they are that specific to one cause then it is for the minority of sufferers, if not the rare few. For some, one exogenous factor may be enough to cause an eating disorder i.e. rape survivors are at a significantly increased risk without any pre-disposing inheritable traits, psychopathology or familial dysfunction.
The Genetics of Eating Disorders
One on-line article succinctly discussed two prominent studies on the genetics of eating disorders. www.edbites.com (October 22, 2013.) In one study, researchers looked at two families over the course of three generations. In one family, ten out of the twenty family members had full-syndrome AN or BN. The researchers looked at various chromosomes and then fully sequenced the genomes of one to two people from each family who had AN to look for any specific mutations among them. (Cui, et. al, 2012. The Journal of Clinical Investigation.)
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“In the first family, they found a single nucleotide mutation in the estrogen-related receptor α (ESRRA) gene. All ten individuals with an ED had this mutation, and nine of ten without an ED did not. In the second family, gene mutation was discovered as well but these mutations were identified by direct genome sequencing, and it’s basically pretty much certain that these mutations are responsible for the astronomical rates of AN or BN [in these two families.]”
The research findings reported that, “The caveat is this: most people with EDs probably don’t have these mutations. These are rare mutations with VERY strong effects, unlike most gene variants thought to contribute to AN, which are slightly more common and have smaller effects.“
The second prominent gene study involved twins. (Bulik, et.al. (2006. Prevalence, heritability, and prospective risk factors for anorexia nervosa. 2006. JAMA. Psychiatry.) The researchers found that roughly 55% of the reason some twins developed AN while others did not was due to genetic factors. However, when researchers examined the billions of DNA based pairs of chromosomes in the human genome, they were unable to consistently find any gene that was definitively linked to an increase AN risk. “The twin studies were consistent across different populations, indicating that genetics was a major factor in AN (and all EDs), but any actual genes remained mysterious.”
Moving forward: From genes to mood
As we progressed from the assertion that genes cause eating disorders, to possibly there is a genetic link based on a series of potential genes, the field of eating disorders began to explore biologic determinants underlying causation. Significant studies on depression and anxiety as pre-determining factors in the development of eating disorders proved reliable and gave and continue to give reason to be hopeful for patient recovery and in pursuing efficacious treatment protocols. (see Kaye, Strober, Fairburn)
Many patients with eating disorders have depression and/or anxiety prior to the development of the eating disorder. In this way, symptoms of the disorder can elevate mood as the sufferer relies on restriction or weight control to compete or fit in to the cultural norm and media expectations. Anxiety can also be controlled through food restriction and purging, both in terms of psychological and emotional buoying and as a physiological release of stress.
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Beyond Anxiety and Depression to inheritiable traits
There were still may inexplicable similarities among patients with eating disorders that research on genes and mood could not fully explain. Most common similarities among sufferers, particularly those with Anorexia Nervosa, are perfectionism, high degree of self-criticism and shame, and the need to maintain control over one’s environment i.e. controlling food intake.
Bulik concluded in her research of genetic factors in twins with Anorexia Nervosa that “Anorexia nervosa is a moderately heritable psychiatric disorder that may be predicted by the presence of early neuroticism…..Neuroticism refers to emotional instability, low self-esteem, and feelings of anxiety, depression, and guilt. The construct of neuroticism is extraordinarily robust…. neuroticism or a very similar construct can be found in essentially every major theory of personality.”
Seizing on the Theory of Personality
Dr. Bulik added a psychological dimension, based on her 2006 research summary, that opens the door to the psychology of eating disorders and perhaps brings us full circle back to understanding eating disorders in a multi-determinant manner.
Although some research asserts that ‘neuroticism’ and ‘perfectionism’ may be inherited traits, psychoanalytic and psychodynamic theories contend that they can also be defensive constructs, that is, the result of psychological conflicts and/or family and relationship stressors or influences. (see Anna Freud. The Ego and the Mechanism of Defense.) Continued research in early childhood attachment patterns, family influences, psychological conflicts regarding guilt, anger, sexuality can also contribute to a person adopting a defensive stance where neuroticism and perfectionism are attempts to deal with intra-psychic conflict.
The field continues to both narrow down and broaden in scope in terms of understanding causation. Why does this matter? Knowledge is power. Understanding causation enables the field to develop more reliable treatment methods and protocols. Increasing the number of people who can recover from an eating disorder is the ultimate goal.
Hopefully, the professional community is beyond categoric and rigid statements about causation. Clinicians and researchers are working together and most are in agreement that the cause of eating disorders are complex and multi-determined. This bridge is an important one that has been crossed, especially for patients seeking help.
