A University of California, San Francisco, study finds medical marijuana laws in a state don’t directly affect how young people view the drug, Forbes reported Friday. In general the study published in the American Journal of Public Health found younger folks have a permissive view of pot.

The researchers wrote, via Forbes:

“This raises the possibility that the progressive liberalization of marijuana control policies at the state level has culminated in a national debate that is influencing all young Americans regardless of the states they dwell in. ... Our analysis also suggests that more permissive attitudes may be drivers in the liberalization of state marijuana control policies.”

The researchers looked at national drug surveys from 2004 to 2013 and analyzed responses — studying attitudes on marijuana riskiness, accessibility and social acceptability — from hundreds of thousands of people between the ages of 12 and 25.

The country as a whole has also grown more permissive toward marijuana. Four states — Washington, Oregon, Alaska and Colorado — and Washington, D.C., have passed legislation to legalize the drug recreationally for adults 21 and older, and more states have it on the ballot in the upcoming year. Twenty-four states along with the District of Columbia have made marijuana legal for medicinal purposes.

GettyImages-494691400 While millennials have increasingly backed marijuana legalization, the attitudes of older generations are beginning to shift, as well. Photo: YURI CORTEZ/AFP/Getty Images

A Gallup poll last year found 58 percent of Americans supported legalization. A recent CBS poll found 56 percent of people in the U.S. support recreational-use legalization while a full 90 percent support medicinal use. 

While the younger generation has increasingly backed marijuana legalization, the attitudes of older generations are beginning to shift, as well. In 2000 and 2001, just 17 percent of people ages 65 and older supported legalizing marijuana. Thirty percent of the 50-64 age bracket in during the same period supported legalization. That generation’s attitude seems to have shifted in the last 15 years, since 35 percent of Americans age 65 and older now support legalization.

Gallup acknowledged that some of the shift nationally over time was due to more permissive generations replacing older generations. However, “the increase in support nationwide is also a function of attitude change within generations of Americans over the course of their adult lifespans,” it concluded.