The growth of on-line casinos offers new temptations for problem gamblers, but the Internet should also provide avenues to treat them, according to a report in a leading medical journal on Wednesday.

The report, published in The Lancet, found that researchers have made progress recognizing and understanding gambling disorders but need to keep pace in the future with the growing access to gaming opportunities.

It is a moving target, said David Hodgins, a professor of psychology at the University of Calgary who co-authored the report, which reviewed the status of studies and treatments for problem gambling.

The desire to wager appears almost universal, but studies have found sharp variations between countries and regions on the percentage of people whose urge to gamble for money can be classified as a pathological problem.

In Norway, one in 500 people are thought to have a gambling disorder, while in Hong Kong the rate is thought to be as high as one in 20. Only 10 percent of problem gamblers seek treatment, according to the report.

The American Psychiatric Association identified pathological gambling as an impulse control disorder in 1980, and is currently examining the criteria used for its diagnosis.

Problem gamblers sometimes treat themselves by avoiding public places where they can wager, but the Internet provides a new challenge by allowing them to gamble in the privacy of their homes, the report said.

It is much more difficult to avoid online gambling, Hodgins said in an interview, noting that gambling sites often solicited potential clients via email.

But the Internet will also encourage more studies on how to treat gambling disorders, possibly offsetting the problems caused to problem gamblers by access to online gaming, Hodgins said.

Structuring Internet forums to help people in the same way they are used by self-help support groups, such as Gamblers Anonymous, is among the ideas being explored by researchers.

Problem gamblers often have other psychiatric disorders or substance abuse problems, but there is a lack of studies into how to deal with those situations, according to the Lancet report.

Hodgins said researchers must examine how the overlapping problems could be addressed at the same time to prevent people from switching addictions.

(Reporting Allan Dowd, Editing by Paul Simao)