What’s the classic, go-to narrative anti-pot pundits rely on to scare people away from using cannabis?
It’s got to be myth that smoking pot will turn you into the Hollywood stereotypical “stoner,” the dude sitting on the couch baked out of his mind, too brain dead to do, say, or think anything productive.
Basically, this classic PSA:
In recent years, marijuana naysayers have relied heavily on a 2012 study published by researchers at Duke University that claimed that intellectual “impairment was concentrated among adolescent-onset cannabis users, with more persistent use associated with greater decline.”
Since then, however, the study has come under significant criticism.
“A follow-up study in the same journal found that the original research failed to account for a number of confounding factors that could also affect cognitive development, such as cigarette and alcohol use, mental illness and socioeconomic status,” Christopher Ingraham explained.
And now, most recently, researchers in the U.S. have published a study in which they tracked the intellectual development of twin pairs throughout adolescence and into adulthood.
In the study, “they focused on 3,066 participants who were given a battery of intelligence tests at ages 9 to 12—before they had used marijuana—and again at ages 17 to 20,” The Associated Press explained.
They were trying to see whether or not marijuana use had any direct bearing on the life trajectories of young people.
After analyzing the data, researchers concluded that there’s no way to definitively link drops in IQ to marijuana use.
Not only did the study fail to find any correlation between marijuana use and IQ changes, but it also undermined the earlier Duke study.
That study, the authors of the newly published twin project say, “fails to support the implication . . . that marijuana exposure in adolescence causes neurocognitive decline.”
Rather, they point out, “children who are predisposed to intellectual stagnation in middle school are on a trajectory for future marijuana use.”
Basically, what these researchers found is that young people who are already not as demonstrably smart as their peers tend to be more likely to become heavy marijuana users, but marijuana use is not in any real way the cause of their lower intelligence scores.
“We found there was no difference between twins in terms of how much their IQ changed,” said Joshua Isen, an author of the study.
“The twin who didn’t use marijuana showed as much IQ drop as the twin who did.”
This means that we have yet to discover the real culprit for why some young people experience intellectual stagnation and others don’t. But at least now we can cross marijuana off the list of possible suspects.