Thursday, June 12, 2008

Addicted to Starvation: The Neurological Roots of Anorexia


This is a great article from the current issue of Scientific American Mind, now available for free at the Scientific American site. Treating anorexia as an addiction may be one valuable way of dealing with the disease. Potentially, it could open a pharmaceutical approach to treatment, since the current use of antidepressants does little good.

One of the curious findings is that many anorexics feel more energetic on their starvation diets. And contrary to what might happen to the rest of us, their metabolism actually increases rather than decreases. This may be a result of the increase in dopamine they experience.

Addicted to Starvation: The Neurological Roots of Anorexia

Anorexia may represent a profound psychiatric disorder that spawns an addiction to deprivation

By Trisha Gura

A recent tabloid captured the common wisdom about anorexia nervosa. In an interview, actor Christina Ricci blamed the pressures of success for her prior struggle with the disease. The headline flashed, “Ricci: Hollywood made me anorexic.”

But did it? True, anorexia is characterized by compulsive dieting or exercise to get thin. And the pursuit of thinness in contemporary culture—particularly in Hollywood—has become a seemingly contagious obsession. Yet there is thin, and then there is emaciated. Crossing over that line means a loss of a basic survival instinct—to eat in response to hunger—that culture should not be able to touch.

What is more, cultural cues cannot easily explain why the afflicted, who are shockingly skinny, misperceive themselves as fat. Anorexics also say they feel more energetic and alert when starving: starvation boosts their metabolic rate, which is in stark contrast to the slowing of metabolism that occurs in most people during a fast.

Such mysteries cry out for a biological explanation. To find one, researchers are probing the brains of anorexics; their work is painting a new picture of anorexia as a multifaceted mental illness whose effects extend far beyond appetite. The illness is accompanied by disturbances in the brain’s reward circuitry that may lead to a general inability to feel delight from life’s pleasures, be they food, sex or winning the lottery. As such, the ailment shares characteristics with drug addiction—the drug in this case being deprivation itself. The study of anorexia, therefore, may yield insights into brain mechanisms for producing pleasure and how something as seemingly unpalatable as starvation or extreme asceticism might, oddly, give rise to a sense of hedonism.

An estimated 0.5 to 3.7 percent of girls and women in the U.S. suffer from anorexia, according to the National Institute of Mental Health. (One tenth as many males experience the illness.) At least two thirds of anorexics do not fully recover even after years of the current treatment, which consists largely of psychotherapy. As a result, anorexia still holds the record for the highest mortality rate (up to 20 percent) for any mental illness in young females. Cutting that death rate will require a new approach, experts say. “People have long been blaming families and media,” says psychiatrist Walter Kaye of the University of California, San Diego. “But eating disorders are biological illnesses, and better treatments will come from more biologically-based approaches.”

Diet as a Drug
Most people abhor dieting. But when a person with anorexia diets, he or she actually feels better—more alert and energetic—when starving. Anorexics do feel hunger pangs; they simply find ways to override them. Dieting becomes the ultimate accomplishment, a fix that a certain kind of dieter learns to crave.

The lack of food may function like an addictive drug for anorexics, says biologist Valerie Compan of CNRS in Montpellier, France. Almost every drug of abuse acts on the brain’s natural reward circuitry—and in particular on a pleasure hub called the nucleus accumbens—to boost the levels of a signaling chemical, or neurotransmitter, called dopamine. The release of dopamine prompts good feelings and also produces the “high” in the case of many abused drugs. Some such drugs, including the highly addictive club drug ecstasy, also suppress appetite—a clue that a refusal to eat might somehow arise from abnormal activity in the brain’s reward system.

In October 2007 Compan and her colleagues found some evidence for that idea. When the researchers injected ecstasy into the nucleus accumbens of mice, the rodents acted like anorexics. When they were offered food, the animals did not eat much, and when food was withheld, they did not work to get it. Ecstasy suppressed the rodents’ appetites, the researchers determined, by stimulating a receptor for the neurotransmitter serotonin. Activating that receptor on neurons in the nucleus accumbens led to the production of a neuro­transmitter associated with addiction called CART (for cocaine- and amphetamine-regulated transcript) that ultimately depressed the desire to eat.

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I would be remiss here if I didn't mention that Internal Family Systems Therapy has been one of the most successful psychotherapies for dealing with the various trauma-related mental illnesses, including especially eating disorders and self-harm disorder.

The model does a great job of separating out the "part" that starves the client, or cuts the client, and determines its role as a protector of another part that is often very young and very vulnerable, a part that was "exiled" as a result of abuse (most often) or some other form of trauma.

When that protector part can be isolated and negotiated with, it will often allow access to the exiled part so that it can be healed. Once the exile has released its "burden," the protector will no longer need to do its job (of staring or cutting) and its energy can be reallocated to something more healthy.

This sounds like magical thinking to some people, but it is remarkably effective. Relapse is far less common in this approach than in traditional psychotherapies.


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