How to Get Monkey Off Your Brain

But Dewey shed new light on cueing in a study of cocaine-addicted rats that were given Vigabatrin. Prior to taking the epilepsy drug, the rats habitually scurried over to the part of their cage where the cocaine was located. With Vigabatrin in their systems, the rats ran around freely and mostly ignored that spot.




"This research has fundamentally changed the traditional view that physical function and brain function are separate," says Alan Leshner, head of the American Association for the Advancement of Science. "The mind-body split is dead and now we know that all addictions are diseases of the brain."


Brookhaven researchers are certain that, though counseling and behavioral adjustments will always play a role in treating addiction, biochemistry-changing medications are the key. "Alter a protein here or there," says Volkow, "and you turn a philanderer into a monogamist."


Volkow believes some individuals may have a predisposition to addiction-a physiological one, caused by an inherent shortage of dopamine receptors. They may be born with fewer receptors, or their brains may have lost receptors over time due to negative life experiences. Such people would be victims of a double whammy: a shortage of dopamine receptors makes them prone to addiction, and then the habit disables even more receptors. In a study completed late last year, PET scans showed that 15 recovering speed addicts had 10 percent to 16 percent fewer dopamine receptors than did 20 people who never used drugs. Similar results have been obtained from studies of alcoholics and cocaine and heroin users. Cause and effect are still unclear, but Volkow believes flawed physiology is partly to blame. "A low level of receptors will drive them to where nothing else but the drug matters," Volkow says.


Brookhaven research has also recently revealed that the withered dopamine systems of addicts are consistently associated with low metabolic activity in the orbitofrontal cortex, the part of the brain that makes it possible to do several tasks at once. The full implications of this finding are unclear, but it may mean that the orbitofrontal cortex is the command center of addiction in the brain. If that's the case, the Brookhaven researchers will have unearthed the location of what some researchers call the "receptors in a haystack"-the few dopamine receptors among the tens of thousands in the brain at which a targeted addiction control drug should be aimed.


There's a certain logic to substance abuse being lodged in the orbitofrontal cortex. This part of the brain also directs obsessive and compulsive activities-and few people are more obsessive than drug addicts. Volkow's next phase of investigation will be to determine whether drug addiction and obsessive-compulsive disorders-the uncontrollable urge, for instance, to pull out each strand of hair or collect every scrap of paper-are nothing more than distortions of healthy survival instincts, distortions that are caused by dopamine-system malfunctions. "New mothers are obsessed with their babies, but that's a positive survival instinct," Volkow says. "Uncontrolled gambling, eating, or substance abuse have the same kind of drive, but they're destructive."