Marijuana and the Brain

9 Jan 2013

Many states across America are trying to figure out how to legally deal with marijuana. Much effort is being spent on treating cannabis as an economic, criminal or political issue. My concern is focused on the medical consequences of smoking pot. Much has been written about the “gateway” effect of marijuana to more dangerous drugs in the youth of America, but what about the primary effects of smoking pot regularly as a recreational drug on cognitive function of adolescents in the US.

Beyond the “gateway” issue what happens to the developing brain of our youth from exposure to cannabis? The first exposure may occur while in the uterus of an expectant mother who is smoking cannabis. Two recent studies demonstrate that prenatal marijuana exposure damages the developing child’s brain in several areas: impaired intelligence decreased short-term memory, attention problems and teenage depression. The second exposure may take place during adolescence. Regular teenage marijuana use has now been demonstrated to lower your intelligence quota (IQ) over the next several years of your life. The IQ can decline as much as 8-10 points by age 38. Longer follow up data is not yet available. Likewise, the combined effects have not been elucidated.

This takes me back to the “gateway” issue. A recent long term follow up study of youth who continue to use cannabis regularly showed that it will lead to higher rates of smoking cigarettes, and higher use of legal (alcohol) as well as other illicit drugs.

While there is a strong push by several forces in our culture to accept marijuana, the medical literature is becoming replete with long term data that it is much more devastating to the brain of our youth than previously thought. If the mantra is truly about “let’s do it for the children,” this is clearly an area where we “should not do it for our youth.” Making cannabis an accepted part of the culture will have irreversible long term medical consequences on our youth that are presently being ignored.

References: Journal of Epidemiology and Community Health 66:e26; July 2012. Journal of the American Academy of Child and Adolescent Psychiatry 49:561-72, June 2010. Neurotoxicology and Teratology 34:161-7, Jan 2012. Journal of the American Academy of Child and Adolescent Psychiatry 47:233-5, March 2008. Proceedings of the National Academy of Sciences Aug 2012 (published online doi:10.1073/pnas.1206820109).