Who remembers this anti-drug PSA in the 80s and 90s where they smug guy whips out a raw egg, cracks it and tosses it into a frying pan saying, “This is your brain… this is your brain on drugs. Any questions?” It’s too bad he forgot to add alcohol into the mix, because the authors of a new study published in the journal Addiction, have linked chronic alcohol consumption with lower gray matter volume in the brain.
Gray matter matters
Gray matter is composed of neuronal cell bodies and is the key information processor within the brain. In fact, scientists believe that the more gray matter someone has, the more intelligent they are.
There are more than 20 regions of the brain where the density of gray matter is directly linked to IQ since these areas are associated with memory, language, and the ability to focus.
Researchers from the University of Colorado, Boulder and Oregon Health and Science University aimed to,
Test the strength of association between (1) alcohol use and GM [grey matter] volume; (2) alcohol use and white matter (WM) integrity; (3) cannabis use and GM volume; and (4) cannabis use and WM integrity among adults and adolescents.
Neuroimaging data taken from groups of adolescents and adults showed that alcohol use resulted in adverse changes in brain structure; changes that were not at all found in cannabis use.
Alcohol use and subsequent brain damage
These findings are unsurprising given that alcohol’s damaging effects on the brain have been widely researched for decades. The U.S. Department of Health and Human Services have reviewed several common disorders that are associated with alcohol-related brain damage, as well as the severe impacts of alcohol withdrawal.
Their study conducted in 2004 found that “male and female alcoholics both showed significantly greater brain shrinkage than those not suffering from alcoholism.” They also note that cognitive issues, learning, and memory are all severely impacted by moderate to heavy drinking.
Weed and the teen brain
As far as cannabis is concerned, the data revealed that “No associations were observed between structural measures and past 30-day cannabis use in adults or adolescents.” The discovery is key, given that there has been much speculation about the effects of cannabis on the developing teenage brain especially.
Natalie Castellanos-Ryan, lead author of a study which measured the effects of pot on cognition and high school drop-out rates found a link between higher drop-out rates and lowered academic success when using cannabis.
When it came down to the direct impacts on the brain, impairment was found in the areas of IQ and specific cognitive abilities related to the brain’s frontal lobe.
While cognitive decline in teens should be a cause for concern, any teen who has access to and heavily uses any substance is most likely going to perform poorly in school. She admitted that brain impairment did not seem to be ‘global or widespread,’ her suggestion; don’t smoke pot before the age of 17.
We found that adolescents who started using cannabis at 17 or older performed equally well as adolescents who did not use cannabis.
Unless used medically, cannabis is for grown-ups only
For adults, however, a peer-reviewed study conducted in 2016 concluded that there were in fact, changes in gray matter for heavy cannabis users but the changes were only linked to those who have been heavy smokers since before early adulthood.
Otherwise, they found a “lack of significant differences in GM [gray matter] volumes between young adult heavy cannabis users and health controls over time.”
This suggests that heavy cannabis use does not reduce gray matter volume, so long as heavy smoking began in adulthood.