Obesity is a mental illness, says a leading U.S. addictions expert, and extreme cases should be classified as a brain disorder.
Nora
Volkow, director of the U.S. National Institute on Drug Abuse, says
brain circuits in obese people can become disrupted, producing an
uncontrollable, compulsive and "pathologically intense" drive for food.
People
overeat and can't stop "even when they desire to do so," Volkow and
Charles O'Brien, of the University of Pennsylvania, write in an
editorial published this year in the American Journal of Psychiatry.
Volkow
says some forms of obesity should be included in the new edition of the
Diagnostic and Statistical Manual of Mental Disorders, psychiatry's
official "bible" of mental illness.
Now in its fourth edition,
the manual catalogues more than 300 conditions and their symptoms, from
anti-social behaviour to voyeurism, and has been controversial since
the first edition was published in 1952. Homosexuality was listed until
1974, under sociopathic personality disorders.
The next issue of the dictionary of mental illness, used by doctors worldwide, is due in 2012.
"Both
food consumption and drug use are driven by their rewarding
properties," Volkow and O'Brien write, floating the theory that
overeaters are chasing the same "high" as a drug user.
And they
say that just as drug use destroys the ability to say no to drugs,
overeating sugary and fatty foods makes people unable to exert
self-control over their food intake.
The result: "over time, massive weight gain."
"I'm
not referring to just anyone who is overweight," Volkow said. "It's the
extreme cases in which the compulsion is so severe it basically
disrupts their life, their professional lives, their health, their
social interactions."
She says the DSM recognizes eating
disorders such as anorexia and bulimia but not obesity, "despite its
devastating medical and psychological consequences."
Recognizing
obesity as a psychiatric illness would lead to new drugs targeting
brain circuits that deal with motivation, drive and condition, Volkow
says.
Arya Sharma says some forms of obesity are clearly tightly
linked to addictive behaviours. But, "I would definitely not say this
is the majority of obese people," said Sharma, scientific director of
the Canadian Obesity Network. "A lot of people say: 'For me, obesity
has nothing to do with addiction; I have control over what I'm eating,
I make proper choices and still I'm obese.' We know a lot of people
like that."
If some people are fat because they binge-eat, "then,
of course, that needs to be characterized under the category of a
mental disorder," Sharma said. And binge-eating ("eating, in a discrete
period of time, e.g. within any two-hour period, an amount of food that
is definitely larger than most people would eat in a similar period of
time under similar circumstances") is already listed in the DSM.
Stuart
Kirk, professor in the School of Public Affairs at UCLA and co-author
of Making Us Crazy: DSM: The Psychiatric Bible and the Creation of
Mental Disorders, says sweeping obesity, or some part of it, under the
"psychiatric tent" is the latest attempt to pathologize human problems
and expand the boundary of what constitutes a psychiatric disorder.