The frequent use of cannabis is not associated with changes in brain structure, according to data published online ahead of print in the journal Addiction. Authors reported, “[N]ormal variation in cannabis use is statistically unrelated to individual differences in brain morphology as measured by subcortical volume.”
Giving remarks to the Native American Housing Association, Housing and Urban Development Secretary Ben Carson strayed into the marijuana reform debate. Unfortunately, the doctor did not know his facts.
Cannabis use by teens is not independently linked with adverse changes in intelligence quotient or executive functioning, according to longitudinal data published online ahead of print in the journal Addiction. Investigators concluded, “Short-term cannabis use in adolescence does not appear to cause IQ decline or impair executive functions, even when cannabis use reaches the level of dependence.”
The cumulative use of cannabis by adolescents has no direct effect on intelligence decline, according to longitudinal data published today in the Proceedings of the National Academy of Sciences. Investigators concluded: “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.”
Marijuana use by adolescents is not associated with lower IQ or poorer educational performance once adjustments are made for potential confounders, specifically cigarette smoking, according to longitudinal data published online ahead of print in the Journal of Psychopharmacology. Researchers concluded, “In summary, the notion that cannabis use itself is causally related to lower IQ and poorer educational performance was not supported in this large teenage sample.”
NORML’s Deputy Director today on Alternet.org addressed new media claims that cannabis use can potentially shrink the brain.
Investigators at the University College of London analyzed data from 2,612 subjects who had their IQ tested at the age of eight and again at age 15. They reported no relationship between cannabis use and lower IQ at age 15 when confounding factors such as alcohol use and cigarette use were taken into account.
The mainstream press has been abuzz in recent days regarding the findings of a recent study suggesting that early-onset, persistent cannabis exposure by those under age 18 could potentially pose adverse effects on intelligence quotient. Yet, absent from the media’s discussion of the study — a discussion that has even included some fairly critical reviews of the study’s methodology (See here and here for just two examples.) — is any talk of the role that marijuana prohibition plays in inadvertently steering young people toward cannabis, an issue I address in […]