The majority of marijuana users believe the myth that it’s a harmless, non-addictive drug. They may even extol the medicinal value of the drug, despite the fact that the FDA has never approved its use for the treatment of any medical conditions. They may not be aware that recent research indicates that marijuana use can have a lasting effect on the brain.

Dr. Nora D. Volkow, Director of the National Institute on Drug Abuse, recently highlighted current marijuana research on the NIDA website. One of the most important research projects is a major new study that indicates that heavy marijuana use by teenagers can lead to a drop in IQ in adulthood.…