Marijuana Use Does Not Lower Intelligence
Researchers at the University of Colorado Boulder have debunked the myth that marijuana use lowers IQ. According to scientists, smoking marijuana does not affect a person’s intellectual abilities.
The First Study on the Effects of Cannabis Use
In 2012, a group of American scientists published the results of a study on the impact of marijuana on cognitive abilities. The study involved volunteers aged 13 to 38, who participated in interviews and took tests to measure IQ and decision-making skills. The results showed that people who began using marijuana in their teenage years performed worse on cognitive tests compared to peers who never used cannabis. The dosage and duration of cannabinoid use directly influenced the degree of decline in intellectual function.
The authors concluded that marijuana has a neurotoxic effect, which can lead to a reduction in IQ if cannabis is used before the age of 18. Based on these results, medical professionals issued a verdict: “Smoking marijuana reduces cognitive functions, especially in teenagers.”
Marijuana Does Not Reduce Cognitive Abilities
To confirm or refute the theory about the harmful effects of cannabis on intelligence, specialists from the University of Colorado Boulder conducted their own research program, involving 428 pairs of twins. The scientists administered IQ tests and compared the scores of twins who used marijuana with those of their siblings who did not. Based on the 2012 hypothesis, the experts expected that non-using twins would score higher. However, in practice, this was not the case: the researchers found no significant difference in intelligence levels among the volunteers.
The lead researcher, Megan Ross, believes that the 2012 study did not account for secondary factors related to environment and genetics. As a result, the earlier study drew the incorrect conclusion that marijuana negatively affects cognitive functions. Ross asserts that their research more accurately reflects reality, as the university team assessed the volunteers multiple times (during adolescence, young adulthood, and before starting marijuana use), using methods to measure the following characteristics:
- Intelligence level
- Decision-making ability
- Speed and intensity of response to stimuli
- Working memory capacity
None of these indicators decreased as a result of cannabinoid use. Therefore, the claim that marijuana makes people less intelligent is not scientifically supported. However, the project does have one limitation: it included only a small number of volunteers who were heavy cannabis users. Because of this, the researchers plan to repeat the experiment, this time involving more people who use marijuana in high doses.