How Decriminalization Has Changed Marijuana Use In The US

Since 2002, more Americans are using marijuana, they spend more money on the drug, and use it more frequently, according to a new study by Steven Davenport, policy analyst at Pardee RAND Graduate School and Jonathan P. Caulkins, professor of public policy at Carnegie Mellon University.

This isn't particularly surprising, because during this time many states have liberalized their marijuana laws, with 18 states decriminalizing the substance and many more allowing for medicinal use.

But the findings of the study of marijuana use, based on the National Survey on Drug Use and Health, reveal a complex picture of the trends and demographics of frequent users. Since the study only covers the years between 2002 and 2013, though, it does not tell us much about recent legalizations of recreational marijuana.

Davenport and Caulkins find that the average weight marijuana sales has declined without the price dropping, which suggests that the potency of the drug has increased. And indeed, this finding is consistent with previous studies, as well as anecdotal suggestions, which indicate that marijuana grown these days has a higher content of THC, the chemical that makes people "high," than previous strains had.

The authors attribute this change, in part, to the increase in medical marijuana dispensaries.

Overall, the trends in the marijuana market point to greater "professionalization" — this means that more people are buying pot outright, rather than informally trading or sharing.

"Previous analysis of NSDUH data and also ethnographic studies ... have characterized retail marijuana distribution as being embedded within existing social networks and is sometimes done at cost or as a favor, not just purely for profit," the authors wrote. "While these traits continue to characterize much of retail marijuana distribution, particularly that the sources were rarely strangers, there is a clear shift from gifting toward selling."

As the market becomes more professionalized, it has become less risky legally, the study noted.

"The criminal risk per marijuana transaction has fallen by half, such that now there is only one marijuana arrest per every 1,100 transactions," the authors wrote. They argue that much of the impact of the "War of Drugs" on the marijuana market is overstated, though racial minorities continue to be disproportionately targeted in these arrests.

And who is doing most of the buying?

In answering this question, Davenport and Caulkins focused on the individuals who purchase the largest amounts of marijuana, rather than on people who just use it occasionally.

They found that people with less than a high school degree, and those who earn less than $20,000 a year, disproportionately used the most marijuana, compared to their share of the population. For those making less than $20,000 a year, their marijuana use increased by 4 percent more than the national trends.

In fact, the more educated and higher-earning groups had lower rates of marijuana use.

Users are also more likely to use marijuana at much higher rates. While at the beginning of the study period, only 11 percent of people who reported marijuana used in the past month had used on at least 20 days during the time, that number was 34 percent by the end of the study.

"I continue to be surprised that one-in-three past-month cannabis users report more than 20 days of use in the past 30, and that half of use days go to cannabis users with a high school diploma or less," Davenport told Patch in an email.

Yet despite many fears, the rollback of marijuana criminalization nationwide does not appear to have increased the rates at which youths use the drug, a finding which is consistent with recent data out of Colorado. Over the period of the study, children ages 12 to 17 were the only group whose use of marijuana actually declined significantly.

But for low-income users, the financial cost marijuana purchases place on their budgets represents a substantial burden.

"As a percentage of income, marijuana spending appears fairly manageable for the most users, but for some, it can be overwhelming," the researchers noted. "Marijuana spending is especially burdensome for more frequent users with lower incomes: [daily or near-daily] users over 21 years old without college degrees spend on average nearly 9% of household income."

They continued, "That impact is perhaps underappreciated by Americans who are better-educated and keep non-problematic marijuana habits: as a portion of income, college graduates without signs of abuse or dependence spend only one quarter of that amount."

There are still many questions about American marijuana us that we don't have answers to, Davenport noted.

"I'd like to further study how to tie and/or untangle increases in daily/near-daily use from increases in cannabis abuse/dependence," he said. "It would also be interesting to monitor similar data in states that have undergone policy changes, e.g., looking at data in Colorado and Washington in 2014 and following years post-legalization."

If current legal changes continue and marijuana laws are further relaxed or eliminated, the authors expect to see these trends continue and potentially accelerate, while prices will likely drop. This means marijuana will likely get more potent, and those using it will use it more frequently. The proportion of low-income people using marijuana may continue to rise.

Photo credit: U.S. Fish and Wildlife Service