NEW YORK (AP) — New research shows more U.S. adults are using marijuana, using it more often and far fewer think it’s risky.

That’s understandable, experts say, as dozens of states now allow medical marijuana and four states have recently legalized pot for recreational use.

More than a half million U.S. adults participated in the survey over a dozen years, and the responses show a shift in attitude. Only a third of adults in 2014 said they thought weekly marijuana use was dangerous, down from half of adults in 2002.

The study was published online Wednesday by the journal Lancet Psychiatry.