Most likely you don’t read the journal Addiction, so if you read an article referencing it, you can’t just pull out your copy to check that the article has referenced to it accurately. You take the article at face value.
Reading an online discussion of marijuana legalization efforts, one of the comments stated the opinion that cannabis makes you stupid, with a link to an undated and very brief article from Men’s Fitness. That article in turn referenced a study by Wayne Hall about a 20-year study of cannabis use that found that long-term use of marijuana does make you stupid, as well as at least sometimes leading to:
- Schizophrenia
- Hallucinations or other “psychotic symptoms”
- Reduced learning, memory, and attention
- Addiction
You also become “twice as likely to die from crashing your car.” Wow.
That didn’t fit with the most reputable research I had read. There was a link, so I clicked on it – It is always good to increase one’s knowledge and challenge one’s preconceptions – expecting to be taken to the Addiction article upon which Men’s Fitness had based this astounding report.
Instead I was taken to a 2014 article from the Daily Mail, a UK tabloid that has often been accused of sensationalism and bad science – hardly a trustworthy source, especially since it didn’t link to the Addiction article either. Maybe the Men’s Fitness editors didn’t know that, didn’t care or just took it on faith because like Jeff Sessions they’re against cannabis use.
Actually, the Wayne Hall paper doesn’t say what the Daily Mail or Men’s Fitness or – according to the Washington Post, which did include a link to the original paper, or at least an abstract – most of the media claimed it said.
- Take the car-crash statistic. The report actually says that “driving while cannabis-impaired approximately doubles car crash risk,”not of dying. You could argue that doubling the risk of a car crash also doubles the risk of dying in a car crash, but that’s not a given.
- It doesn’t say that it permanently doubles your overall risk, just while you are high. Drinkers are at risk when drinking or intoxicated, too. Duh.
- The severity of the accident can depend on other factors, such as how fast you are driving. People impaired by cannabis usually are driving slower. Of course, you can still have an accident – slower reflexes, less concentration – but it’s less likely to be fatal.
- The article fails to mention that alcohol and both marijuana with alcohol causes far more accidents than marijuana alone. There’s not even a standard or test for what constitutes marijuana intoxication, only the presence of marijuana in the blood or urine (which can linger for days or even weeks).
- A National Highway Traffic Safety Administration study, “Drug and Alcohol Crash Risk” by Richard P. Compton and Amy Berning, “did not show a significant increase in levels of crash risk associated with the presence of drugs,” particularly marijuana, when adjusted for “age, gender, ethnicity and alcohol use.”
And that’s just from parsing one sentence in the article.
Marijuana use is not absolutely harmless – neither is sugar, caffeine or alcohol – and its use can become serious enough of a problem to require substance use disorder treatment. With marijuana legalization increasingly likely – at the state level at least – the best hope for keeping marijuana regulated requires honest assessments of its risks and benefits, not scare tactics out of embarrassing exploitation films Reefer Madness and Marihuana: Weed with Roots in Hell.
