The effect of cannabis on the developing brain has been a topic of interest for decades. As more and more US states legalize and decriminalize the use of cannabis, several studies have been conducted to ascertain whether cannabis does actually make you dumb.
Today, cannabis is being regulated by the US government as a Schedule I drug, thus putting it in the same category heroin, MDMA and LSD. This classification translates to it being a substance that “has a high potential for abuse.”
According to 2015 government data, 15% of 10th-grade students and 21% of 12th-grade students have used cannabis in the past month. Past research has already proved that people who started smoking cannabis as a teen are more likely to get addicted, and recent research published in the Proceedings of the National Academy of Sciences journal, stated that if you smoked cannabis heavily as a teen, it can actually lower your IQ.
A 2016 study carried out on about 300 students by the University of Montreal and published in the Development and Psychopathology journal revealed that teenagers who started smoking around 14 years of age performed woefully on some cognitive tests by age 20 than non-smokers. They are also known to have a higher school dropout rate.
Another study from New Zealand carried out in 2007 showed that cannabis use is associated with reduced intelligence. A 1996 study of Costa Rican men and a 2002 US study of pro-longed cannabis users were linked with poorer memory; or poorer attention and verbal skills, according to report from a 2010 research.
However, a couple of other studies have revealed the absence of any long-term relationship between cannabis and IQ. A 2005 study from Canada and a previous 2004 study on twins by researchers at Boston University both attest to this.
Although new research has contested the idea that cannabis use negatively affects cognitive ability, it might be inconclusive. Also, most of the studies that claim cannabis use negatively affects cognitive ability didn’t consider other key aspects like working memory or executive function (including judgment, decision-making ability, and other higher cognitive skills).
Other inconsistencies in the studies carried out revealed that some twins dropped out of the research. If those that left were heavy users than those that remained, the inherent effect of massive cannabis use would have been missed. Does Cannabis Make You Dumb? In all, we cannot dismiss the possibility that cannabis use does have a negative impact on teenager’s brains, especially in ways that appear only after decades.