RALEIGH, N.C. (AP) – Annual boosts to family income – like the casino payments received by members of the Eastern Band of Cherokee Indians – may play a role in steering teenagers away from alcohol and marijuana use, according to a study published Tuesday.

An article in the Journal of the American Medical Association by a group of Duke University Medical School researchers reported that members of the tribe who were about 12 years old when the annual payments started were far less likely than older counterparts and all non-Indians to have substance abuse problems as adults.

Annual payments for Cherokees grew from about $500 to $9,000, an amount the authors say is probably unrealistic to see repeated on a national basis.

“Income support for poor families at this level would be an enormous investment of public resources,” the report said. “However, the costs of social control of delinquent behaviors, including drug problems, are also very high.”

The key may not be money, though, according to lead author Jane Costello, but rather removing a major source of worry from domestic life.

“Reducing stress on families is what has an effect,” she said. “In this case, we were able to demonstrate that an increase in income is what reduced the stress, but there could be other ways.”

The researchers interviewed nearly 1,200 people in western North Carolina from an original group of over 1,400, who had been tracked starting in 1993. Once the Harrah's Cherokee Casino and Hotel opened in the middle of the decade, members of the tribe began receiving annual payments, but nonmembers did not.

That gave the researchers a chance to compare the effects of the yearly payments on two populations – Cherokees and non-Cherokees – who were largely similar in economic background.

The youngest children, who were about 12 when the payments started, benefited the most.

Among that group, about 14 percent of Cherokees have developed a problem with alcohol in adulthood, compared to 24 percent of non-Cherokees. About 10 percent of the youngest Cherokees report a problem with marijuana as adults, compared to 16 percent of non-Cherokees.

Older Cherokees, such as those who were about 16 when the income supplements started, were more likely than non-Cherokee to have problems with alcohol and drugs as adults, however.

The younger Cherokees also had lower rates of substance abuse in general and psychiatric disorders, along with fewer instances of trouble with the law and higher levels of education.

“We can't say whether it was because they were young when the payments started or because they were receiving the payments for a longer period of time,” Costello said.

A call to the Eastern Band of Cherokee Indians was not immediately returned Tuesday.