How Does Cannabis Use Affect Teenage Brains?

Cannabis affects teens differently from adults

“This is your (teenage) brain.”

*Demonstrates perfect, whole egg*

“This is your brain on drugs.”

*Cracks egg into hot pan—egg dramatically sizzles*

That unforgettably powerful piece of film is an excellent example of the way the anti-legalization movement has educated the masses on marijuana: use extreme, scary statements and provide no evidence.

Since the influx of Mexican refugees during the early nineteenth century’s teenage brain on drugsMexican Revolution, the government has used racially motivated propaganda and misinformation to stigmatize and criminalize marijuana.  The end result is the DEA’s Drug Schedule, which classifies cannabis as a Schedule 1 drug, or a substance with a high potential for abuse and no medical use.

That classification is odd given the many medicinal benefits attributed to cannabis, and even stranger when considering the FDA’s approval of the countless, highly addictive opioid-based pharmaceuticals killing Americans at epidemic proportions.

It can be difficult to trust the government when such hypocrisies and perversions so easily make themselves known, but what if, when it comes to adolescents and cannabis’ effect on their brain development, the government is getting it right?

Does cannabis negatively affect teenage brains?

The answer to this question is complicated, particularly because of a lack of longitudinal studies, or studies which gather evidence on the same subjects over a long period of time.  In order to properly understand the way that brain development is affected by cannabis use, researchers really need to examine the adolescent brain before and after use over an extended period of time, which obviously presents some difficulties.  For one, legal cannabis use is fairly nascent, but even where cannabis has been legalized, it is restricted to adults aged 21 and older.  Secondly, it is ethically challenging for researchers to encourage cannabis use when it is suspected of having adverse reactions on brain development.

During the teenage years, the brain does some important developing.  It actually prunes itself in order to remove unnecessary connections, and that process improves judgment, critical thinking, and memory.  Some studies actually do suggest that adolescent cannabis use coincides with significant alterations in the brain’s gray and white matter, brain tissue containing synapses and responsible for carrying nerve impulses between neurons.

These changes may adversely affect cognition and academic performance.  A longitudinal Duke University study analyzing IQ changes in 38 marijuana users and nonusers found that people who began consumption during adolescence lost approximately eight IQ points between childhood and adulthood.  The change seemed to be correlated with amount.  The teenage cannabis use affects IQmore pot the person smoked and the earlier the age, the greater the decline in IQ.  The study also found that adults who began smoking as teens had poorer memory and decision making skills than adults who had abstained from pot.

Another study found that adolescents who began smoking prior to age 16 and who smoked five days a week demonstrated damaged white matter, and those users had a harder time controlling their impulses, planning, remaining flexible, and thinking abstractly.

But these studies aren’t perfect, and the answer to the question remains murky.

So… maybe not. 

The study that found damaged white matter in the brains of heavy smokers focused on… heavy smokers.  But not all adolescents consume marijuana 5 times a week, so it is hard to say if the subjects of that study simply represented the extreme end of the spectrum. The Duke University study that demonstrated a decline in IQ had a significant issue as well.

The marijuana smokers had the lowest IQs even before they were marijuana smokers

And this highlights one of the biggest problems with studies aimed at uncovering the effect of cannabis on adolescents: it remains unclear if cannabis causes the issues, or if the adolescents are predisposed to the issues to begin with.

Adolescent cannabis users may already be people who have a hard time fitting in or socializing, and those qualities may attract them to the subculture of marijuana use and predispose them against institutional norms like academic success and conformity.

The American Psychological Association concedes that adolescent marijuana use is correlated with some pretty negative outcomes including low academic performance, increased high school dropouts, high rates of welfare dependence, unemployment, and malaise.  But the APA also states that these outcomes may not entirely be cannabis’ fault.  Environmental factors, emotional trauma, or a predisposition for problematic behavior are all variables that could lead to negative life choices and experiences, and it is extremely difficult to untangle those factors from the actual effects of cannabis use.

One study attempted to separate the effects of cannabis from genetic predispositions and environmental influence by examining the brains of 241 same-sex siblings, some of whom were twins.  Siblings who smoked demonstrated similar brain anatomy to their nonsmoking siblings.  This finding suggested that that there may indeed be certain genetic and environmental elements that predispose people to use marijuana, and those predispositions may affect the way the substance influences the brain.  The adverse response a teen has to marijuana may have more if not as much to do with that particular teen’s brain than with the cannabis itself.

The safe bet. 

So is the old commercial’s symbolic egg sizzling an accurate comparison of the way the brain is impacted by cannabis?  As silly as that question even sounds, it’s really hard to say definitively.   The paucity of research answering that question won’t allow any hard conclusions.

For that reason, it’s probably best that teenagers play it safe.

Technically, adolescents aren’t allowed to use marijuana since the legal age of consumption is 21.  For that reason alone, teens should abstain.  Law enforcement has a pretty bad relationship with marijuana users, so a teenager using marijuana is putting himself/herself in unnecessary risk of getting in serious trouble with the law.

And brain development is no joke.  While the therapeutic benefits of cannabis are real, it may not be worth the risk to engage in cannabis culture too soon, especially if there is no medical need.  It is probably also safe to assume that kids who are accessing marijuana are doing so through the black market, and a lot of that marijuana isn’t tested for things like pesticides and mold, making consumption a definite health risk.

At the end of the day, though, teenagers are going to do what they want, and that puts a lot of the onus on parents and guardians.  The condescension of cracking an egg on a pan and using sweeping generalizations to create fear and judgment likely will not resonate with most teens.  As marijuana continues to become more and more mainstream, it is critical that parents communicate honestly with their kids about the value and risks of cannabis consumption.

Knowledge is power, especially when the knowledge is based in factual information, not propaganda, and when it comes from a place of love and curiosity, not fear and animus.

How Does Cannabis Use Affect Teenage Brains? was last modified: by
Dianna Benjamin
About Dianna Benjamin
Dianna Benjamin is a freelance writer, teacher, wife, and mom horrified and fascinated by social justice and our inability--yet constant pursuit--to get it right.