For Teens – Marijuana Can Have Lasting Effects on the Brain

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.

The study, which was conducted in New Zealand, involved a long-term survey of 1,000 individuals. Researchers measured each participant’s IQ at age 13 and then again at age 38. When the two IQ scores were compared and correlated with marijuana use, an undeniable pattern emerged. Individuals who started using marijuana heavily as teenagers (i.e., more than four days per week) and continued heavy use into adulthood showed a significant loss in intellectual ability.  There is also the possibility of physical and mental addiction that may require marijuana rehab.

The average drop in IQ for those who used marijuana heavily as teenagers was 8 points. For an individual with an IQ of 100 points, a drop of 8 points can mean a shift from medium intelligence to the lower third of intelligence ranking. The study also found that the drop in IQ scores between was less significant when heavy use began after adolescence. For participants who never used marijuana, there was no change in IQ.

The study indicates that marijuana can be toxic to the brain during adolescence, a period of critical development. Of particular significance is evidence that marijuana’s effect on the teenage brain is lasting and that permanent deficits can be caused by the drug. The study appears to lend credence to the media stereotype of the spaced-out teenage stoner.

A national survey on drug abuse in America has found that marijuana is the most abuse drug in the nation. The National Survey on Drug Use and Health, which included roughly 70,000 randomly selected teenagers and adults, reports that 7% of those surveyed classify themselves as regular users of marijuana. This is up from 5.8% in 2007. According to the National Institutes of Health’s Monitoring the Future Survey, the number of teenagers who currently smoke marijuana on a daily basis is at a 30-year high, fueled by the misperception that frequent marijuana use carries little risk of harm.