For America's 6 million compulsive gamblers, the long odds are on a pill.
In the largest clinical study of its kind, researchers at the University of Minnesota found that daily doses of an experimental drug called nalmefene, often used to treat alcoholism, appeared to curb the craving to gamble, according to research published this week.
The new research represents the latest effort to control the biology of misbehavior at a time when celebrity poker, online gambling, lotteries and sports betting have helped to make obsessive wagering a national psychiatric disorder.
"The study is part of emerging evidence that gambling, once thought to be a problem in moral integrity, is instead a problem in brain biology and can be successfully treated," said Dr. Robert Freedman, editor of the American Journal of Psychiatry, which published the study in this month's issue.
Sponsored by BioTie Therapies Corp., a Finnish biotechnology company that manufactures the drug, the researchers tested nalmefene in a controlled trial involving 207 people under treatment for compulsive gambling at 15 centers across the United States.
Almost two-thirds of the patients showed "significant" improvement during the four months of treatment with nalmefene, compared with one-third who responded favorably to a placebo, the researchers reported.
More than a third of the original participants dropped out because of nausea and other side effects.
The new compound "offers a real promise of hope for folks with this problem," said Dr. Jon E. Grant, a University of Minnesota psychiatrist who led the study.
In the effort to treat pathological gambling, researchers have long sought some way to control cravings long enough for more conventional counseling to become effective.
Part of the difficulty is that compulsive gamblers often are not easily convinced that they have a problem.
"Gambling itself is quite pleasant. It is the fallout - bankruptcy, divorce, jail - that is unpleasant," Grant said. "It is difficult to keep people in treatment."
In the search for a biomedical solution, researchers have experimented with other medications, such as serotonin inhibitors and lithium, that have had mixed results in limited studies. A third promising treatment for the disorder, involving a drug called naltrexone, turned out to cause severe liver damage.
"Up to now we only had inklings that a pharmacological agent would be successful," said Grant, who said he had no financial stake in BioTie.
The key is to take the compulsive thrill out of winning and losing.
Nalmefene interferes with brain opiate circuits that process sensations of pleasure. It also indirectly affects the brain's dopamine system, which handles feelings of reward.
Treated with nalmefene, the patients reported that gambling no longer seemed so thrilling or so compelling.
"It is not a magic pill," Grant said. It may be most effective when used in conjunction with traditional counseling and therapy.
To better understand proper dosages, the researchers are conducting a second clinical trial involving 200 patients at 20 treatment centers, he said.
Robert Lee Hotz writes for the Los Angeles Times.