Move over, Stoner Sloth! Smoking weed actually doesn’t make you stupid.
Two new studies have been published that disprove the infamous 2012 Duke University findings that heavy marijuana use as an adolescent and young adult corresponded with a decline in IQ.
In a new study published January 6, 2016, British researches asked, “Are IQ and educational outcomes in teenagers related to their cannabis use?” To find out, scientists observed 2,235 adolescents from ages 8-16, tracking grades, test scores, and IQ points in relation to cannabis use (or lack thereof) while adjusting for outside factors such as mental health and use of other substances.
What the study ultimately found is that “cannabis use by the age of 15 did not predict either lower teenage IQ scores or poorer educational performance. These findings therefore suggest that cannabis use at the modest levels used by this sample of teenagers is not by itself causally related to cognitive impairment.”
While the British study didn’t directly disprove Duke’s 2012 claims, the American one did.
Researchers tracked the “life trajectories” of identical twins, one who used marijuana and the other who did not. (Identical twins have almost exactly the same genetic makeup, are raised in the same home, and share the same environmental factors, making them ideal for controlled studies like this.) After examining the pairs of twins over the years, scientists found that the twin who used marijuana did not experience “greater cognitive deficits” than the twin who abstained, disproving the unsettling findings of Duke’s 2012 study.
The twin study “fails to support the implication by (the authors of the Duke study) that marijuana exposure in adolescence causes neurocognitive decline,” the study concludes. Furthermore, the study argues that if marijuana use was directly linked to cognitive decline, then the more marijuana a person smoked, the less intelligent they would become; however, the study found that heavier marijuana use was not associated with a parallelled greater decline in IQ.
As the nation continues to emerge from the residual fog of reefer madness, more research can be conducted to help disprove less-informed past claims and lift the veil of fear and ignorance from voters’ eyes. This is just another example of good things to come — how fast they’ll come, however, remains to be seen, much hedging on the presidential election and rescheduling of marijuana to allow more scientific research.