If you’re a parent and don’t know how to talk to your teenagers about marijuana, think about what the President of the United States said in a The New Yorker article. He said that he would tell his two daughters that it’s a bad idea, a waste of time, and not very healthy.
Former President Barack Obama also expressed support for legalization, describing his past drug use as “a bad habit, a vice,” similar to smoking cigarettes, which he had recently quit. He also said that marijuana is not more dangerous than alcohol. Many parents in his youth would have been shocked by such comments. In the 1970s, there was a big movement against marijuana. This movement stopped any serious discussion about making it legal in the United States and Canada. The movement was based on fears that marijuana use would lead to laziness and reduce economic competitiveness.
But the conversation about marijuana is changing quickly. Now, most people support decriminalization or legalization. But some scientists studying marijuana’s impact on the teenage brain say that young people need more detailed information than simply being told it’s “not very healthy.”
Researchers have raised concerns that the focus on reducing aggressive prosecutions, facilitating access to medicinal marijuana, and regulating its supply to undermine the black market has led to a lack of public-service messages about the health risks for adolescents, who are the primary users. For example, in Canada, although usage rates have declined over the past decade and only 10% of adolescents report regular use, Canadian teens still have the highest levels of marijuana use among developed nations, according to a 2013 UNICEF report. A World Health Organization (WHO) study found that 28% of children aged 11 to 15 had tried marijuana in the past year. Many of these adolescents seem to be replacing cigarettes with marijuana, viewing it as safer and more beneficial for their health.
However, research indicates that adults and adolescents face different risks. While a 30-year-old might use marijuana with relatively minimal risk, adolescence is a critical period for brain development, and marijuana use during this time can have potentially life-altering long-term consequences for some individuals.
The message of “wait until you’re older” is likely to be dismissed by most adolescents, as it has become a well-worn cliché over the years. This sentiment is reinforced by its widespread use among teenagers. However, when compared to the significant health risks of binge drinking and the addictive, cancer-causing effects of smoking, marijuana’s perceived harmfulness seems relatively minor. Obama’s stance reflects a common perspective among parents who have smoked marijuana and later switched to other substances without experiencing adverse effects. For most adolescents, especially those who use marijuana infrequently and begin in high school, a similar pattern is likely. Nonetheless, scientific evidence suggests that modern marijuana is more potent than it was in the 1970s. Research indicates that marijuana can alter brain development in a subset of teenagers who start using early and consume it heavily, potentially leading to long-term issues with working memory and even triggering genes associated with schizophrenia.
Adolescents must be aware of the potential risks of marijuana use, as emphasized by Yasmin Hurd, a neuroscientist at New York’s Mount Sinai School of Medicine specializing in marijuana studies. She highlights that marijuana can significantly impact a teenager’s life trajectory. “And how does one determine whether they are more susceptible to such effects?” she asks.
Despite marijuana being used for centuries, scientists still know very little about it. Most studies focus on heavy users, and many marijuana effects are subtle, making it unclear how these findings apply to occasional users. It is known, however, that adolescence is a crucial period for brain development, during which cross-brain connections form in the temporal lobe, a central hub for working memory and reasoning. A recent review of 120 Canadian and U.S. studies found that early marijuana use alters brain development. A McGill University study linked daily marijuana use in teens to depression and anxiety, though the connection to mental health issues like schizophrenia remains unclear. Some scientists believe that teenagers who use marijuana early and heavily might be self-medicating, and that this use could interact with genetic predispositions to trigger illnesses. A U.S. study found that individuals with schizophrenia who did not use marijuana had similar working memory problems and brain function changes as those who did not have the disorder but used marijuana heavily.
While some scientists argue that marijuana use can lead to harder drugs like cocaine and heroin, others disagree, noting that many teenagers do not progress to such substances. However, studies on young rats show a clear link between marijuana and addiction, with effects potentially lasting a long time. In a joint U.S.-Canada experiment released last year, the “grandchildren” of teenage rats given one joint every three days were more likely to seek heroin, even if their “parents” had not been exposed to marijuana.
Nonetheless, as Hurd acknowledges, animal studies demonstrate neurological effects in a controlled laboratory setting, whereas humans are influenced by complex environmental, societal, and genetic factors that can act as protective barriers against marijuana’s potential dangers. Still, Hurd emphasizes the need to investigate whether marijuana can alter the brain in ways that increase teenagers’ likelihood of experimenting with other substances over time. The results of such research could provide crucial insights.
Reducing marijuana’s dangers for teenagers would be a positive development. One strategy could involve implementing stricter regulations on the type of marijuana available and its accessibility. A 2012 U.S. study found that legalizing medical marijuana did not increase its use among teenagers. In contrast, European countries with more liberal marijuana laws have lower rates of teenage use compared to Canada. Benjamin Hansen, a co-author of the 2012 study, suggests that while lower prices might make marijuana more affordable for adolescents, regulated suppliers would limit third-party sales to minors, thereby reducing demand for illicit substances. Hansen further states, “Presently, the most opportune individual for a dealer to engage with is a 15-year-old adolescent.” He then asks, “How probable is it that this adolescent is an undercover law enforcement officer?”
Experts believe that making marijuana legal for adults but keeping it illegal for teenagers could encourage people to seek treatment for problematic use. This approach could also increase research into addiction treatment options, which are currently limited. Dr. Didier Jutras-Aswad, a researcher at the University of Montreal who studied rats over many generations, says that only about 10% of marijuana users become addicted, compared to about 32% of nicotine or cocaine users. But, since so many people use marijuana, the number of people struggling with addiction may be higher. As people continue to talk about whether to legalize marijuana, Jutras-Aswad says that society can learn from what it did and did not learn from its experience with alcohol. It took decades to develop standards for healthy use, control driving under the influence, and provide clear public health messages. We can do the same with cannabis. We can make rules to stop problems before they start. For teenagers, this means setting aside the politics and rhetoric and focusing on the facts.