How to Get Monkey Off Your Brain

Meanwhile, naltrexone, a treatment for alcoholism and opiate abuse, blocks drug-induced highs by shutting down sites in the brain that make people feel good-banishing not only the addiction but much of the reason for living as well. No wonder today's anti-addiction drugs are unpopular. "If we take away pleasure, no one's going to take the treatment," says Stephen Dewey, senior scientist at the Department of Energy's Brookhaven National Laboratory in Upton, New York.


Promising new research, however, may help put these primitive drugs behind us. In the past decade, investigators have learned a remarkable amount about the brain chemistry that makes mood-altering drugs so pleasant-and, thus, so difficult to quit-as well as the precise location of addiction in the brain. Once these neuro-mysteries have been fully puzzled out, researchers hope to design targeted substance abuse treatments that act more like cruise missiles than cannonballs, quelling cravings without deadening the pleasure of everyday life. Their efforts stand to improve the lives of more than 65 million Americans hooked on everything from cigarettes to crack. "Addiction will always be with us," says Frank Vocci, director of the Division of Treatment Research and Development at the National Institute on Drug Abuse, "but these new drugs are our first real opportunity to minimize it."


Brookhaven is the epicenter of this ambitious project. There are many other anti-addiction research programs-60 different compounds are being developed to treat cocaine abuse alone-at schools such as Johns Hopkins, Emory, Harvard, and the University of Pennsylvania, and at agencies like the National Institute on Drug Abuse (NIDA). But backed by an annual $5 million budget, a team of a dozen scientists at Brookhaven has launched the most elaborate effort yet to map the mechanics of the addicted brain with advanced imaging technology. Their main focus: a chemical called dopamine, the prime mover in the human pleasure pathway.


Dopamine is one of the brain's many neurotransmitters-chemicals that carry messages between brain cells. These chemicals travel through the brain by hopping from one cell to the next. After being secreted by one brain cell, a neurotransmitter must bind to a specialized receptor on the next cell in order to continue its journey. Dopamine's main job is to ferry information related to elation and pain. The joy we get from a meal, a promotion, a winning poker hand, or sex-anything that brings us happiness-is conveyed in part by dopamine. But only recently have scientists literally visualized dopamine's dark side: specifically, the role it plays as the brain's principal architect of drug addiction.


Under normal circumstances the brain produces dopamine at a relatively constant rate, and only a portion of its dopamine receptors are occupied at any given time. But under the influence of a mood-altering drug like cocaine, the brain releases an avalanche of pleasure-inducing dopamine. With so much of the chemical available, practically all of the brain's dopamine receptors become activated at once.