New study highlights significant increases in cannabis use in United States

Many countries around the world are considering revising cannabis policies. A new study by a researcher at Carnegie Mellon University assessed cannabis use in the United States between 1979 and 2022, finding that a growing share of cannabis consumers report daily or near-daily use and that their numbers now exceed those of daily and near-daily alcohol drinkers. The study concludes that long-term trends in cannabis use parallel corresponding changes in policy over the same period. The study appears in Addiction .

“The data come from survey self-reports, but the enormous changes in rates of self-reported cannabis use, particularly of daily or near-daily use, suggest that changes in actual use have been considerable,” says Jonathan P. Caulkins, professor of operations research and public policy at Carnegie Mellon’s Heinz College, who conducted the study. “It is striking that high-frequency cannabis use is now more commonly reported than is high-frequency drinking.”

Although prior research has compared cannabis-related and alcohol-related outcomes before and after state-level policy changes to changes over the same period in states without policy change, this study examined long-term trends for the United States as a whole. Caulkins looked at days of use, not just prevalence, and drew comparisons with alcohol, but did not attempt to identify causal effects.

The study used data from the U.S. National Survey on Drug Use and Health (and its predecessor, the National Household Survey on Drug Abuse), examining more than 1.6 million respondents across 27 surveys from 1979 to 2022. Caulkins contrasted rates of use in four milestone years that reflected significant policy change points: 1979 (when the first data became available and the relatively liberal policies of the 1970s ended), 1992 (the end of 12 years of conservative Reagan-Bush-era policies), 2008 (the year before the U.S. Department of Justice signaled explicit federal non-interference with state-level legalizations), and 2022 (the year for the most recent data available). Among the study’s findings:

“These trends mirror changes in policy, with declines during periods of greater restriction and growth during periods of policy liberalization,” explains Caulkins. He notes that this does not mean that policy drove changes in use; both could have been manifestations of changes in underlying culture and attitudes. “But whichever way causal arrows point, cannabis use now appears to be on a fundamentally different scale than it was before legalization.”

Among the study’s limitations, Caulkins says that because the study relied on general population surveys, the data are self-reported, lack validation from biological samples, and exclude certain subpopulations that may use at different rates than the rest of the population.

Addiction

10.1111/add.16519

Changes in Self-Reported Cannabis Use in the United States from 1979 to 2022

22-May-2024