Scientists Seek Clues to the Brain’s Destructive ‘Pleasure Pathways’
The rush of placing a bet is remarkably similar to the high from snorting cocaine or the buzz from drinking Scotch. Scientists and addiction specialists say that is no coincidence.
Compulsive gambling stimulates the same “pleasure pathways” in the brain that respond to drugs and alcohol, says Dr. David Comings, who has conducted pioneering research on the subject at the City of Hope Medical Center in Duarte.
“Once we found it, we weren’t surprised,” says Comings, whose recent work, based on blood samples, was the first to show a genetic link between compulsive gambling and dopamine, the chemical in the brain responsible for various pleasurable feelings, everything from eating to having sex.
Like earlier studies of drug addicts and alcoholics, research on compulsive gamblers shows “there are certain people who are more susceptible to gambling than others in the general population,” Comings says.
Dopamine is a neurotransmitter, a vital ingredient in the soup of chemicals that regulates the brain’s overall function. It acts upon thousands of receptors embedded in passages throughout the brain.
Scientists have linked dopamine to many self-destructive behaviors--not only drug abuse and alcoholism, but also smoking, overeating and compulsive sex, Comings says. People with shortages of dopamine may physiologically compensate through activities that release more of the chemical into the blood.
Those who have gambling problems may not necessarily develop other forms of addiction because their pleasure need has been satisfied by compulsive betting, says Dr. Eric Hollander of the Mt. Sinai School of Medicine in New York.
“That’s why, with the increased access to legalized gambling, we’re seeing a dramatic increase” in problem gamblers, he says. Still, Hollander says, half of all compulsive gamblers suffer at least one other addiction.
Hollander is now examining two other brain chemicals that may be affected when someone places a wager.
One is serotonin, which inhibits impulsive actions and regulates anxiety and mood. Too little of it opens the door to obsessive and compulsive behavior.
The other chemical is norepinephrine, a cousin of adrenaline that controls general arousal.
“When we stimulate serotonin receptors in the brain . . . we can actually provoke a sense of high, a rush or euphoria that is very similar to the rush that gamblers get when they start to gamble and win,” Hollander says.
Other researchers have reported dramatic results by concentrating on electrical activity in the brain. In one laboratory, casual gamblers and compulsive gamblers strapped on electrodes to compare brain wave activity as the two groups engaged in controlled wagering.
Casual gamblers showed the expected result: They reacted more to winning than to losing and were more stimulated by playing for real money than by gambling with nothing at stake, says Charles A. Warren, who made the comparison recently at the Gambling Addiction Center at the University of Illinois at Chicago.
Compulsive gamblers, meanwhile, showed heightened brain wave activity in every situation, with money on the line or not. Unlike casual gamblers, who reacted most intensely to the thrill of winning, the compulsive gamblers showed a greater response to losing, as if success caused their brains to “kind of shut down,” Warren says. “It’s almost like they . . . are seeking to lose, like they feel a certain rush from the loss.”
The expanding knowledge may lead to drug treatments. In two recent trials conducted by Hollander in New York, 14 of 20 patients who received the drug fluvoxamine completely stopped gambling. The results of the initial trial were published this month in the American Journal of Psychiatry and may lead to far wider trials of fluvoxamine and other medications.
“We believe the majority of patients really can benefit,” Hollander says.
