Science & Health
Legal Marijuana Sales Don’t Increase Use, But Allowing Possession Does, Study Finds
When penalties for marijuana possession are lifted, usage rates seem to increase—but that’s not the case when retail sales of cannabis are permitted. Those are the findings of a new study that seems to run contrary to a key talking point of groups that oppose legalization.
To learn how different reform policies impact consumption trends, researchers at Colorado Mesa University analyzed survey data from more than 1,400 people over the course of 17 months in Colorado, Washington and Australia. Their findings were recently published in the journal Substance Abuse: Research and Treatment.
While some prohibitionist groups have proposed simply removing penalties for possession as a preferred alternative to full commercial marijuana legalization—which they believe will create an industry incentivized to increase heavy cannabis consumption—the new study appears to undermine that position.
After Washington State instituted voter-approved legalization of cannabis consumption and possession, but before retail sales were allowed, there was a 12-22 percent spike in use among college undergraduates in the state.
However, the researchers “found no evidence” that the subsequent implementation of legal sales of recreational cannabis “influenced the number of marijuana users in Washington.”
A similar trend was observed when they looked at data from Australia. The country doesn’t allow legal cannabis sales, but after decriminalizing the plant, there was a 16 percent increase in consumption.
Because the researchers started collecting data from Colorado just three months before retail cannabis sales started, they didn’t reach a conclusion about how removing penalties for possession alone influenced consumption patterns. But the data did show that, in the year after retail sales launched, “rates of marijuana use did not significantly increase.”
The researchers said that the seemingly counterintuitive finding could interpreted a couple ways.
First, it’s possible that “the social and legal implications of legalizing recreational marijuana are stronger than accessibility and price,” they wrote. In other words, ending criminal penalties for cannabis and normalizing its consumption in a social context might lead to an increase in usage “even before it is sold to the public through legal means.”
“It is important to note, however, that it is reasonable to assume that people would be more truthful and more likely to report marijuana use after its legalization,” they wrote, referring to common study methodology that relies on consumers’ own self reports to track usage levels. “Thus, some of the increase in rates of marijuana use may be an artifact of a greater willingness to report such use, since social and legal barriers were removed by legalization.”
The other inference that can be drawn from the study is that “marijuana is easily accessed even when it is not sold in stores recreationally.” It may be easy to access prior to removal of penalties for possession, too, but legal and social barriers associated with prohibition could suppress its use—or at least lead people not to report about their consumption truthfully when asked in a survey.
All that said, the study authors emphasized that “the conclusions drawn in this commentary are based on observable patterns from correlational research, limiting conclusions of cause and effect.”
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Photo courtesy of Chris Wallis // Side Pocket Images.
