CHICAGO – Smoking a joint once a week or a bit more apparently doesn’t harm the lungs, suggests a 20-year study that bolsters evidence that marijuana doesn’t do the kind of damage tobacco does.
The results, from one of the largest and longest studies on the health effects of marijuana, are hazier for heavy users — those who smoke two or more joints daily for several years. The data suggest that using marijuana that often might cause a decline in lung function, but there weren’t enough heavy users among the 5,000 young adults in the study to draw firm conclusions.
Still, the authors recommended “caution and moderation when marijuana use is considered.”
Marijuana is an illegal drug under federal law although some states allow its use for medical purposes.