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…