The American Gaming Association has come out with a report saying that the true social cost of individual gambling problems is hard to calculate, given that most people with gambling problems also have "co-existing disorders."

(College of Charleston economics professor Douglas M. Walker) ... pinpointed four areas where he said current research falls short: the effects and costs of co-morbidity or co-existing disorders, findings based on questionable survey data gathered from gamblers, measurements of government costs related to problem gambling, and estimates of societal effects if legalized gambling had not come along.

On the first point, Walker said: “Given that many pathological gamblers exhibit other disorders, it is difficult if not impossible to accurately estimate the social costs attributable specifically to pathological gambling. As an example, consider a pathological gambler who is also a drug addict and engages in behavior resulting in social costs of $5,000."

“What proportion of the cost should be attributed to the gambling disorder and what proportion to drug use?”