SOURCE: Washington University School of Medicine, news release, Feb. 10, 2016
WEDNESDAY, Feb. 10, 2016 (HealthDay News) -- The rise in marijuana use among American adults is not as large as previously suggested, a new study says.
About 12.5 percent of adults said they used marijuana at least once in 2013, researchers found, but adults' use of the drug did not double from 2002 to 2013, as another study reported last fall.
That earlier study also said marijuana-related problems such as addiction also doubled during that time.
The new findings show marijuana use among U.S. adults rose 20 percent between 2002 and 2013, and that the rate of pot-related problems held steady or even declined, according to the researchers at Washington University School of Medicine in St. Louis.
While they found that marijuana use did not double, the 12.5 percent of adults who used the drug in 2013 was a higher percentage than the 9.5 percent reported in the previous study.
The new study was published Feb. 10 in the journal JAMA Psychiatry, which also published the previous findings.
"It's not surprising that marijuana use is on the rise -- several states have legalized it for either medicinal or recreational use -- but our data suggest that the use rate hasn't come close to doubling," study first author Richard Grucza, an associate professor of psychiatry, said in a university news release.
Grucza said the two studies agree that close to one in 10 adults uses the drug. "The difference is that we believe the 2002 survey for the other study underestimated the percentage of adults using the drug," he said.
Despite the increases in marijuana use, the new survey found no increase marijuana-related problems, Grucza said. "Certainly, some people are having problems so we should remain vigilant, but the sky is not falling."
The U.S. National Institute on Drug Abuse has more on marijuana.