Compulsive Gambling May Be Inherited.

• Position: Brief Article

Casinos, gambling boats, and state lotteries are popular ways to raise revenue and provide some excitement for those who play. As legalized gambling has become more common in the U.S., though, problems have sprung up as well. In part, that is because some people are genetically predisposed to certain gambling behaviors, according to researchers at Washington University School of Medicine in St. Louis (Mo.) and the Veterans Affairs Medical Center in St. Louis.

They studied 3,359 pairs of twins to get a better idea of genetic influences on gambling behavior. The sample included both identical twins, who have exactly the same genes, and fraternal twins, who share about half of their genes. "Because all of these twins were brought up in the same household, we can control for differences in formative experiences during youth. Those experiences will tend to be very similar, so with both identical and fraternal twins, we are able to zero in on inherited factors," explains Seth A. Eisen, associate professor of medicine at the university and a staff physician for the Department of Veterans Affairs. "By comparing the sharing of a particular behavior in identical twin pairs with that in fraternal twin pairs, we can estimate the inherited and noninherited contributions to that behavior."

To be diagnosed officially with a psychiatric condition called pathological gambling disorder, an individual must exhibit at least four of nine behaviors, which include gambling larger amounts than intended, irritability if unable to gamble, and sacrificing important activities in order to do so. "We were able to estimate the specific genetic component for two of those gambling behaviors. One was gambling larger amounts than intended, and the other was repeated efforts to reduce or stop gambling. For those two symptoms, we found that about half of the gambling behavior was genetically mediated."

For three other behaviors--attempts to win back losses at the same place...