Adult Marijuana Use Doubles Over Past Decade

According to an article today in JAMA Psychiatry, An estimated 9.5% of adults in this country use marijuana, and 30% of users meet the criteria for marijuana use disorder. These numbers are double those from ten years ago. The work was conducted in the NIAAA intramural lab of Dr. Bridget Grant.

These findings highlight the changing cultural norms related to marijuana use, which could bring additional public health challenges related to addiction, drugged driving and access to effective treatment,” states Nora D. Volkow, M.D., director of the National Institute on Drug Abuse (NIDA), which contributed funding to the study. This and other comments can be found in an NIH-issued press release today.

Other recent findings from NIDA- and NIAAA-funded studies:

At present, 23 states have medical marijuana laws and 4 states and the District of Columbia have legalized marijuana for recreational use. These numbers will continue to rise. The study authors note that public education about the dangers associated with marijuana use will be increasingly important to counteract public beliefs that marijuana use is harmless.

Marijuana Is More Damaging Than You Might Have Thought

Credit: Paul at

Because there is a nationwide move to legalize (or at least decriminalize) pot, there are a lot more studies on   it now. Older studies are not always relevant because there is so much more THC in today’s pot. The National Institute on Drug Abuse (NIDA) just issued a press release about findings reported in a New England  Journal of Medicine article.

Among the not surprising findings: it’s addictive, it impairs driving, and like alcohol and nicotine it’s a gate- way drug. More surprising: using marijuana as a teenager is more damaging than using it as an adult, probably because the brain is not fully formed until one’s early twenties. The damage to memory and cognition  are more pronounced when used by teens. Using it in your early teens permanently decreases one’s adult IQ, even if you don’t smoke as an adult. Another surprising finding: All users have impaired thought and memory while high, but regardless of age, the deficits actually last for days afterward. An estimated 6.5% of 12th-graders nationwide report daily pot smoking, and 60% do not perceive it as dangerous.