Experts estimate as many as twelve people - family, friends, employers, and others, are directly affected in a negative way when an individual becomes addicted to gambling.

In December, 1997, a study on addictions was released by the Harvard Medical School Division. The study showed that while the majority of Americans and Canadians gamble with little or no adverse consequence, the percentage of adults with gambling disorders in the United States and Canada has risen dramatically in the past twenty years and the percentage of teenagers with gambling disorders is significantly higher than that of adults. The study was funded by the The National Center for Responsible Gaming and was a "meta-analytic" examination of 20 years of research on problem and compulsive gambling. It analyzed 120 previous independent studies on problem gambling disorders and is the first such study ever conducted on the issue of problem gambling.

Howard Shaffer, the Harvard associate professor of psychology who directed the study, stated: "As gambling has become more socially accepted and accessible during the past two decades, the general adult population has started to gamble in increasing numbers. We are now beginning to witness a growth in gambling disorders among this group."

According to the study, the prevalence rate of adult compulsive gamblers, estimated at 0.84 percent from 1977 to 1993, rose to 1.29 percent from 1994 to 1997. The rate for the 20 year period was 1.14 percent. Researchers found gambling disorders were significantly more prevalent among adolescents than among adults. The prevalence rate of juvenile compulsive gamblers was 5.77 percent, and the rate of problem gambling was 14.82 percent. The study also showed that gambling disorders were more common among men than among women, but the percentage of problem women gamblers has risen with the increasing availability of slot machines.