About 10 million more Americans smoke marijuana now than 12 years ago, a new study in the British medical journal Lancet Psychiatry has found. The Guardian notes that the study comes as at least five states prepare to vote on whether to legalize marijuana for recreational purposes, including California, which is considered a linchpin in the campaign for federal legalization. The study used data from 596,500 adults surveyed between 2002 and 2014 for the US National Survey on Drug Use and Health to reach its conclusions about how many Americans use marijuana.
One of the study’s key findings is that between 2002 and 2014, the percentage of Americans who said they smoked marijuana at least once in the previous year grew from 10.4 percent to 13.3 percent. That increase equates to an additional 10 million Americans who said they used the drug at least once in the past year, bringing the population who admitted use from 21.9 million in 2002 to 31.9 million in 2014. Those using marijuana daily more than doubled, from 3.9 million to 8.4 million, or from 1.9 percent of the U.S. population to 3.5 percent, over the same period. However, researchers did not find a rise in the proportion of Americans who abused marijuana, called a “use disorder” in psychiatric terms. That number stayed flat at 1.5 percent of the population.