This is pretty much the $64,000 question in the ED world right now. It sounds kind of silly, but the question remains: what causes eating disorders? And the truth is, we don't know. We know what doesn't cause eating disorders, which includes skinny supermodels, bad parenting, and control issues. Do they contribute? Absolutely. But that's different from cause.
I've contemplated this issue for years and have blathered on and on about it in this blog. Yet these several paragraphs from the Around the Dinner Table forum in response to the question " Are EDs a control issue or a chemical imbalance?" by my dear friend IrishUp says it so succinctly and so right on, that I had to share. I could not improve upon this explanation no matter how hard I tried.
There are two distinct issues being conflated in this statement; A) What is the etiology, or natural history, of ED? and B) What is the internal experience of someone who has ED? The former deals with the brain, our most important organ. While our understanding of the brain is in its infancy, the BRAIN is without a doubt a physical, tangible object and we can describe brain structure and function with the languages of science and medicine. The latter has to do with the MIND, and that is a much more elusive thing. It's not tangible. It's mostly subjective. The nature of the mind is best described in the languages of philosophy and theology. And yet, our MIND is a function of the BRAIN. So we've developed the discipline of Psychology to bridge the gap between the tangible and intangible, the objective and subjective, science and philosophy and theology.
Eating disorders are the behavioral expressions of bio-chemical and neurological disorders of the brain. People who exhibit EDs were born with genetic traits that made them susceptible to developing the disorders if and when certain kinds of experiences occur in their environment. The genetics seem to express themselves as high levels of anxiety/social anxiety, OCD, perfectionism, conflict avoidance, and other related traits long before ED occurs. Common environmental triggers include conscious diets, strep infections, trauma or high stress, and incidental periods of insufficient caloric intake (like the kid undergoing a growth spurt, or the athlete whose training intensifies). It looks like, by and large, you need at least one ingredient from each the "nature" and the "nurture" columns to develop ED, and most people have more than one from each. Additionally, the developmental changes the brain undergoes during adolescence seems to play a key role, as the vast majority of EDs exhibit themselves at this stage. Since our social milieu also changes radically during this time, it is likely that the environmental triggers are stronger and/or more common at this stage.
Given the above, someone who has ED may well experience it as "a control issue". In fact, many ED sufferers report that they have (short lived) positive "control" thoughts when they don't eat, and negative "control" thoughts when they do. They also have a tendency to misinterpret other's actions as negative. And to think thier own bodies as larger and shaped differently from how they actually are. But these thoughts are actually a symptom of the disease. This is similar to how people with the classic symptoms of schizophrenia (hearing voices, believing outside forces are controlling their actions, & etc) are having the symptoms because of the neurological imbalances of that disease. In both cases, the person is having real experiences inside their mind that have little to do with the outside environment.
And different still from the physical causes of a disease, or the mental symptoms the disease may cause in our thinking or our understanding while we are sick, is the MEANING we attach to things we experience. Our experience of "what does this all mean?" is ultimately completely subjective, and completely dependent on our belief systems. If we beleive diseases are caused by voodoo curses, or cold unloving mothers, or imperfect faith, or a kind of test from a higher power, or none of the above, or all of the above, our understanding of the disease experience will be framed in terms of that belief.
So if someone states "I got ED because I needed more independence from my father", he's not "wrong", he's just talking about how ED fits into a larger meaning in his life. It also shows that that person is not being exposed to good clinicians who could tell him "Well, yes, you may have needed more independence. However, if you hadn't had the genetic makeup you do, the stress of the situation would not have triggered the development of ED."
Maybe, then, the answer to this cogent question--are EDs culturally-based or biologically-based--is BOTH.