NEW YORK — (CNN) A heck of a lot more Americans were toking up in 2012-13 than 10 years before — and not for medical reasons, either — according to a new study.

The percentage of American adults who had used marijuana within the last year was 9.5%, the study found. That compared to 4.1% in 2001-02.

The study — published this week in Jama Psychiatry, a monthly journal published by the American Medical Association — was sponsored by the National Institute on Alcohol Abuse and Alcoholism. It was based on in-person interviews with more than 36,000 Americans over the age of 18.

With the increase in use has come an increase in the total number of what the study called “marijuana use disorders.”

But the authors of the study put that down to the increase in use: The percentage of pot smokers with such disorders actually dropped, with about one in three showing signs of dependence or abuse.

As the authors of the study put it, “The prevalence of marijuana use disorder among marijuana users decreased significantly from 2001-2013,” from 35.6 percent of users to 30.6.

The attitudes toward the use of marijuana are shifting in the United States, as are the laws governing its use. Twenty-three states now allow the use of marijuana for medical reasons, the study notes, and four of those states also allow recreational use of the drug.

“Given changing laws and attitudes toward marijuana, a balanced presentation of the likelihood of adverse consequences of marijuana use to policy makers, professionals and the public is needed,” the study said.

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