“Burying the lede”: heavy cannabis use in Colorado

“Burying the lede” is what journalism teachers call it when the key fact in a story doesn’t make it to the first (“lede”) paragraph but instead gets “buried” somewhere down in the story.

Of course, scientists can make the same mistake: breathlessly reporting routine findings while ignoring what’s surprising or important. Consider, for example, this week’s report from the Colorado Retail Marijuana Public Health Advisory Committee. The authors report relatively encouraging news about the public-health impacts of legalization: cannabis use among adults and minors is high relative to other states, but there’s no observable increase after the opening of retail adult-use stores. The spike of emergency department visits due to edibles seems to have come back to earth.

But neither the report itself, nor the news stories I’ve seen about it, makes much of a fuss about what looks to me like the headline finding: (from p. 4 of the report):

In 2015, 6% of adults reported using marijuana daily or near-daily. This was lower than daily or near-daily
alcohol (22%) or tobacco use (16%). Of 18- to 25-year old marijuana users, 50% report using daily
or near-daily (13% of all 18- to 25-year olds). Among adult past-month marijuana users, 79% smoke, 30%
“vape” and 33% use edibles. Respondents could report using more than one method, which 50% of users
did. Finally, approximately 2% of adults drove a vehicle in the past 30 days after using marijuana.

In case you didn’t notice it: 50% of cannabis users between 18 and 25 use every day or almost every day. (The report defines “daily or near-daily use” as self-reported us 5 to 7 days per week.) We know from other studies by Beau Kilmer and his group at RAND that daily/near-daily smokers consume about three times as much cannabis per use-day as less frequent smokers, enough to be measurably impaired (even if not subjectively stoned) for most of their waking hours. That turns out to be 13% of the entire population of young adults. The National Survey on Drug Use and Health finds that about one-half of daily or near-daily smokers meet the diagnostic criteria for Substance Use Disorder. That’s a frightening share of users, and of the total population, to be engaging in such worrisome behavior.

The comparison with daily use of alcohol and tobacco seems vaguely reassuring: daily cannabis use is less common than daily use of the two others drugs. But that’s a false reassurance, because the behaviors aren’t directly comparable. Tobacco, of course, isn’t an intoxicant at all. Alcohol certainly is, but as sociological (not pharmacological) fact most drinking activity is not to the point of intoxication: most people who have a drink or two, even every day, just have a drink or two: they don’t intend to get drunk, and they don’t in fact get drunk. The scientific literature has a technical term for getting drunk: it’s called “binge drinking,” and is usually defined as four or more drinks at a sitting for a woman, five or more for a man (to allow for gender differences in weight). Binge drinking is a hell of a lot more common than you’d like it to be: about half of all drinks are consumed as part of drinking binges. But it’s still relatively rare.

Cannabis, by contrast – again, this is sociology, not pharmacology – is, under U.S. conditions and practices, usually used to intoxication, as the common terms indicate: “getting medicated,” “getting stoned,” “getting wrecked.” Yes, it’s possible to take a puff or two before a dinner or a concert, or at a party, to enhance the enjoyment of food, music, and companionship, but that’s not in fact the way U.S. consumers typically take the herb. Of course, some of those daily and near-daily users aren’t getting stoned every time they use; their tolerance for THC has developed to the point where smoking just makes them feel normal. Unfortunately, all the studies show that objective impairment – reduced performance on a range of cognitive and motor tasks – can be present even when subjective intoxication is absent, and in fact impairment generally lasts longer than the feeling of being high.

And yet the prevalence of heavy use doesn’t even make it to the report’s list of “trends to continue monitoring” (i.e., things to worry about), and doing something to bring that prevalence down fails to make the list of recommendations.

More and more people using cannabis more and more often is a trend that pre-dates legalization and is not restricted to states that have legalized. Between 1992 and 2014, as Jon Caulkins calculated, the share of cannabis users who are daily or near-daily more than quadrupled nationally, from 9% to 40%. It’s not clear how much Colorado’s retail non-medical legalization in 2012, or the establishment of retail medical outlets in 2009, or legalization for medical use in 2000, influenced the current prevalence there.

What is clear is that lower prices (Colorado retail bud is now down to about $6/gram and headed lower) and aggressive marketing – both accompaniments of cannabis legalization as it’s currently being pursued, though not of alternative legalization proposals – make it easier for users to slip into heavy daily use. Indeed, that’s the main – some of us would say the only significant – risk of legalization. That risk could be reduced by using taxes to prevent the price collapse  So a report on the effects of legalization that neglects heavy use is like a review of the last performance of “Our American Cousin” that doesn’t mention John Wilkes Booth.