Reward and punishment in anorexia nervosa

A recent review article titled "Theoretical perspective on anorexia nervosa: The conflict of reward," has to be one of the most fascinating scientific reads I've had for a long time (and my Facebook friends can confirm that I read a lot!). The gist of the paper is that many of the behaviors of AN, such as food restriction and excessive exercise, are initially rewarding, they eventually become punishing. An overlap in the neural circuits that process reward and punishment enables these two factors to become all knotted up, or "contaminated."

The author, Charlotte Keating, begins her argument with the concept of anhedonia, or an inability to experience pleasure, which is central to both major depression and a clinical feature of AN. Moreover, excessive exercisers tend to report greater levels of anhedonia, perhaps because exercise is being misused as a mood elevator. Initially, exercise and food restriction are very rewarding, which may be partly why people with AN become entrenched in these behaviors in the first place. Not eating feels better. Exercising feels better. Continued food restriction and excessive exercise only reinforces the reward, leading to the expectation that not eating and over-exercising will make the person with AN feel better.

The problem, says Keating, is that food restriction and excessive exercise are ultimately rather punishing behaviors. So how can punishing behaviors simultaneously be rewarding? The answer appears to lay in the anterior cingulate cortex, which (among many other things) is involved in the processing of reward, punishment, conflict, empathy, and other rational cognitive behaviors. In people with AN, the ACC doesn't process reward the same way; whether ultimately derived from dopamine circuits, reward is blunted in people with AN.

Writes Keating:

"...it may be that hypoactivity in ACC (which reflects the bulk of literature investigating this region in AN) reflects an impaired ability to adjust maladaptive behaviors which may also lead to illness maintenance."

Thus reward-punishment contamination means that the AN sufferer has a greatly reduced capacity for motivation to change, and to regulate his/her pathological behaviors. Furthermore, a low motivation for change only increases the neural "blurring" between reward and punishment.

The ultimate goal is not only to improve motivation to change by decreasing the blurring between reward and punishment in AN sufferers, but also to target "the mechanisms that may be responsible for bringing about behavior modification."

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5 comments:

Anonymous said...

Very cool stuff, Carrie. I love learning from your blog!

Kim said...

Wow, very interesting. I never thought about it like this, but it seems exactly accurate.

Carrie Arnold said...

I, Too, found that this paper explained a lot. I'm curious to see how asceticism factors into the equation as well- I don't know whether or not it would be that blurring of reward and punishment, or a malfunction of the dopamine systems or both. Because I score pretty high on the asceticism scales, and people with AN in general score higher.

What I really liked about the article was the testable hypothesis and clear line of logic and evidence. Keating is still a grad student, and I would love to see what she develops in the future.

Peoples-Health said...

Really a useful post..

The person suffering with Anorexia may be abnormally sensitive about being perceived as fat, or have a massive fear of becoming fat -- though not all people living with Anorexia have this fear. They may be afraid of losing control over the amount of food they eat, accompanied by the desire to control their emotions and reactions to

their emotions. With a low self-esteem and need for acceptance they will turn to obsessive dieting and starvation as a way to control not only their weight, but their feelings and actions regarding the emotions attached. Some also feel that they do not deserve pleasure out of life, and will deprive themselves of situations offering pleasure (including eating).

Blogking said...

I'm sick of people telling me its just a phase when I know people out there dying from eating disorders! Lend a hand; don’t avoid the problem people!!!!

http://www.eatingdisorderclinic.org/?utm_source=blog&utm_medium=pv&utm_content=zs&utm_campaign=home

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I'm a science writer, a jewelry design artist, a bookworm, a complete geek, and mom to a wonderful kitty. I am also recovering from a decade-plus battle with anorexia nervosa. I believe that complete recovery is possible, and that the first step along that path is full nutrition.

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nour·ish: (v); to sustain with food or nutriment; supply with what is necessary for life, health, and growth; to cherish, foster, keep alive; to strengthen, build up, or promote



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