Decline in IQ linked to frequent or dependent use of cannabis use in youth

A meta-analysis of seven longitudinal studies involving over 5,000 participants found that frequent or dependent cannabis use in youth is associated with an average IQ decline of approximately 2 points. The researchers analyzed pre- and post-exposure IQ measures across cohort studies and found a statistically significant effect linking youth cannabis use to intelligence quotient reduction. The study suggests that cannabis exposure during developmental years may have measurable impacts on cognitive functioning.