For decades, it’s been said that using marijuana will lower one’s IQ. But science has just found that there’s no factual basis for this contention. A recently published study concluded that “short-term cannabis use in adolescence does not appear to cause IQ decline or impair executive functions.”
Investigators from the U.S. and UK have studied neuropsychological performance in adolescent twins, according to The National Memo. The authors of the study reported that “family background factors” impacted cognitive performance, not marijuana use. Researchers at the University of California – Los Angeles and University of Minnesota performed similar analysis in 2016 and found the same results.
In the 2016 study, the longitudinal analysis concluded that there was “no significant differences in performance among those who used marijuana and their non-using twins.”
Furthermore, investigators concluded that, “In the largest longitudinal examination of marijuana use and IQ change… we find little evidence to suggest that adolescent marijuana use has a direct effect on intellectual decline…[T]he lack of a dose – response relationship, and an absence of meaningful differences between discordant siblings lead us to conclude that the deficits observed in marijuana users are attributable to confounding factors that influence both substance initiation and IQ rather than a neurotoxic effect of marijuana.”
Earlier this year, researchers in Florida also explored the issue and said, “Our findings did not reveal a significant association between cumulative marijuana use and changes in intelligence scores.”
Political opponents of marijuana reform continue to argue that marijuana use reduces IQ. For instance, Ann Coulter recently commented: “Marijuana makes people retarded, especially when they’re young.”