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Nearly 43 percent of young adults used marijuana in 2021

A cannabis farmer checks his crop in Petrolia, Calif. (Melina Mara/The Washington Post)

Marijuana use among young adults reached an all-time high last year, with nearly 43 percent of 19- to 30-year-olds saying they had used marijuana in the past 12 months, according to research funded by the National Institute on Drug Abuse and conducted by the University of Michigan Institute for Social Research.

The Monitoring the Future report found a steady increase in marijuana usage in the age group over the past decade, rising from 29 percent in 2011 to 34 percent in 2016.

The researchers also reported that use of hallucinogens — psychedelic drugs that alter a person’s perception of reality, such as LSD, peyote and mushrooms — was less common than marijuana use in the same age group, but that it too is increasing, up from 3 percent a decade ago to 8 percent in 2021.

The only hallucinogen to decline in usage was MDMA (ecstasy), down from 5 percent in 2020 to 3 percent in 2021. Monitoring the Future research has tracked substance use in the United States by various age groups for more than three decades.

Study: Kids who vape tobacco are more likely to go on to use cannabis

The latest report found that young adults’ most commonly used substance is alcohol, although its use (whether daily, in the past month or past year) has been decreasing for about 10 years. But binge drinking (consuming five or more drinks in a row) and high-intensity drinking (10 or more drinks) have been on the rise, with 32 percent of young adults saying they binged on alcohol in the prior two weeks and 13 percent reporting high-intensity drinking in that time frame.

Since 2017, the study has also tracked vaping and has identified a continuing upward trend. It found that 6 percent of young adults said they had engaged in nicotine vaping in the past month in 2017, but that number had increased to 16 percent by last year.

Prevalence of marijuana vaping in that time frame grew from 6 percent of young adults in 2017 to 12 percent in 2021. A separate study, published in the journal Addiction, found that marijuana use overall was about 20 percent greater in states that have legalized marijuana than in states where recreational use remains illegal.

This article is part of The Post’s “Big Number” series, which takes a brief look at the statistical aspect of health issues. Additional information and relevant research are available through the hyperlinks.