Summary Of Research On Marijuana’s Negative Health Effects: Teens At Greatest Risk

From National Institute of Health, National Institute on Drug Abuse, News Release, June 4, 2014, "NIDA review summarizes research on marijuana’s negative health effects: Comprehensive review published in the New England Journal of Medicine also discusses why risks are greatest for teen users"

The review describes the science establishing that marijuana can be addictive and that this risk for addiction increases for daily or young users. It also offers insights into research on the gateway theory indicating that marijuana use, similar to nicotine and alcohol use, may be associated with an increased vulnerability to other drugs.

The authors review literature showing that marijuana impairs driving, increasing the risk of being involved in a car accident and that these risks are further enhanced when combining marijuana with alcohol. The authors also discuss the implications of rising marijuana potencies and note that, because older studies are based on the effects of lower-potency (less THC) marijuana, stronger adverse health effects may occur with today’s more potent marijuana. (THC is the psychoactive or mind-altering chemical delta-9-tetrahydrocannabinol found in marijuana.)***The scientists focus on marijuana’s harmful effects on teens, an age group in which the brain rapidly develops, which is one factor that could help explain increased risks from marijuana use in this population. Research suggests that marijuana impairs critical thinking and memory functions during use and that these deficits persist for days after using. In addition, a long-term study showed that regular marijuana use in the early teen years lowers IQ into adulthood, even if users stopped smoking marijuana as adults.

The NIDA-supported 2013 Monitoring the Future Survey says that 6.5 percent of 12th graders report daily or near-daily marijuana use, with 60 percent not perceiving that regular marijuana use can be harmful. “It is important to alert the public that using marijuana in the teen years brings health, social, and academic risk,” said lead author and NIDA Director Dr. Nora D. Volkow. "Physicians in particular can play a role in conveying to families that early marijuana use can interfere with crucial social and developmental milestones and can impair cognitive development."