As critics of marijuana legalization are happy to point out, there are plenty of concerning trends regarding marijuana use in the United States. We’ve collected a number of them below.
1. Overall marijuana use is increasing
Federal survey data show that marijuana use is on the rise overall -- 8.9 percent of Americans age 12 and older used the drug on a monthly basis in 2016, up from 6.2 percent in 2002. In the narrowest public health sense, that’s bad news. The drug is habit-forming, and its use is linked to a number of physical and mental health problems.
The final thing to note in the above chart is that the rate of monthly marijuana use was on the rise well before Colorado and Washington voted to legalize recreational use of the drug in 2012.
2. Heavy marijuana use is increasing
Public health experts say we should worry less about monthly or yearly marijuana use, and more about heavy marijuana use, measured here as the percentage of monthly users who use the drug on a daily or near-daily basis. That share has risen from 32.6 percent in 2002 to 41.7 percent in 2016.
People who get stoned every single day are at the most risk of suffering negative consequences from their use, like decreased cognitive ability, respiratory problems and problems at work. They are also at the most risk of becoming dependent on the drug.
But there’s a puzzle in this data. Federal surveys show that as heavy marijuana use has risen, the share of all Americans who qualifying as having a marijuana use disorder has actually fallen, from 1.8 percent in 2002 to 1.5 percent in 2016, a modest but statistically significant decrease. As authorities define it, marijuana use disorder “occurs when someone experiences clinically significant impairment caused by the recurrent use of marijuana, including health problems, persistent or increasing use, and failure to meet major responsibilities at work, school, or home.”
The reasons for those diverging trends aren’t clear.
3. Marijuana is getting stronger
Thanks to decades of selective breeding and improvements in cultivation techniques, today’s marijuana tends to be a lot stronger than the stuff available 30 or 40 years ago, according to data collected by the Office of National Drug Control Policy. To draw a very crude analogy, smoking a joint in 1968 might have been akin to drinking a can of beer. Smoking one today could be more like doing three shots.
Again, the interesting thing here is that most of this increase in potency happened prior to legalization in Colorado and Washington in 2012. If anything, the available federal data shows that average potency has plateaued and even fallen slightly since then. This gets to a point that many legalization proponents make: Simply outlawing a drug may not be the best way to protect people from the risks of using the drug. And with a relatively benign substance such as pot, outlawing it may actually make dangers worse.
4. In legalization states, more drivers are testing positive for marijuana
A big concern with increased availability of marijuana is an increase in stoned driving. While federal research has shown that marijuana is generally less debilitating to drivers than alcohol, driving while high still significantly increases the risks of crashing your car relative to driving while sober.
Last year, for instance, the Denver Post collected data showing that the number of drivers involved in fatal crashes who tested positive for previous marijuana use rose sharply from 2013 to 2016. But as the Post points out, there’s a big asterisk with these numbers: Because detectable traces of marijuana remain in people’s systems long after they consume the drug, the rising numbers don’t necessarily indicate that THC-positive drivers were impaired at the time of their accidents.
Still, the numbers are increasing fast enough that public health experts are taking them seriously.
5. Marijuana-related ER visits are on the rise
A recent study out of Colorado found that the number of teenagers going to the emergency room or urgent care on account of marijuana use rose sharply from 2009 to 2015, from 1.8 marijuana-related visits per 1,000 visits in that age group in 2009 to 4.5 in 2015.
There are a number of possible explanations for this. Following legalization, more teens may be exposed to pot simply because there’s more of it lying around in Colorado homes. However, the fact that total rates of teen marijuana use are falling in the state casts some doubt on this notion.
Another explanation is that liberalization of attitudes toward marijuana use is making teens more likely to seek out medical help when they feel they need it.