The great risks of marijuana for those under 18: what every parent should know.
Young brains are especially vulnerable to the effects of cannabis.
The following article first appeared in our March 9, 2017, issue of “What I Learned This Week.” To learn more about 13D’s investment research, please visit our website.
In WILTW January 19, 2016, we discussed why marijuana is one of the fastest-growing industries in the world. New Frontier data projects that by 2020 the legal cannabis market will create more than a quarter of a million jobs. That is more expected jobs than government, utilities, and even manufacturing, says the Bureau of Labor Statistics. And now that more than half of U.S. states allow the use of medical marijuana, consuming cannabis is quickly becoming as “normal” as sipping a glass of red wine, or procuring a prescription for adderall. With roughly 20 million users nationwide, the U.S. economy stands to reap enormous upsides — as do those suffering from chronic pain, chemotherapy’s side-effects, or multiple sclerosis.
And yet teenagers could suffer serious downsides. Those are the years when the brain transforms itself from that of a child to the brain of an adult. As Krista Lisdahl, director of brain imaging and neuropsychology at the University of Wisconsin, Milwaukee, explained to NPR: it is a time when “our brain is getting rid of those connections that weren’t really used, and it prunes back. It actually makes the brain faster and more efficient.”
Marijuana, studies show, can disrupt that decisive process. The findings are especially troubling when you consider that 7,000 Americans try weed for the first time every day (up from 1,000 in 2002), and over 60% of them are under the age of 18, according to the Substance Abuse and Mental Health Services Administration.
Lisdahl’s warning, meanwhile, is nothing short of explicit: “It’s a mistake for teenagers to use cannabis. It’s the absolute worst time. Think of the teen years as the last golden opportunity to make the brain as healthy and smart as possible.”
A growing body of scientific literature shows that adolescent brains are particularly vulnerable to the neurotoxic effects of early drug use. That’s because their brains are undergoing crucial neurodevelopmental changes at the exact stage in their lives when they are most prone to taking risks. For instance, brain regions associated with problem solving, memory, and emotional regulation, including the prefrontal cortex, continue to undergo “gray matter synaptic pruning” into the mid-20s, studies report. At the same time, a recent review of the scientific literature concludes that white matter volume and integrity increases into the early thirties, “yielding improvements in efficient neural conductivity.”
For those younger than 16–18, the cognitive downsides can be especially severe. Evidence suggests that regular marijuana use — once a week or more — starting before age 18 actually alters the structure of the brain. In one study, researchers found that adolescents who used marijuana were more likely to have lower concentrations of white matter in their prefrontal cortex, and more likely to be impulsive. Functional MRI studies have reported abnormal brain activity in the prefrontal cortex and parietal regions in early marijuana users versus those who started later. As with early alcohol use, cognitive performance, including overall and verbal IQ, can take a hit.
In one of the most notable studies, researchers from Duke University examined the impact of regular marijuana use on IQ in a longitudinal sample of 1,037 individuals, followed from birth to age 38. The results were clear. Speaking to NPR, the study’s author, Madeline Meier, said:
“We found that people who began using marijuana in their teenage years and then continued to use marijuana for many years lost about eight IQ points from childhood to adulthood, whereas those who never used marijuana did not lose any IQ points.”
Academic performance can suffer too. “Adults who smoked pot as teenagers did worse in tests of memory and decision-making than adults who did not smoke pot as teenagers,” NPR reported. But not before adding this caveat: those who used marijuana most in the Duke study had a lower IQ to begin with. We quote Dr. Gregory Tau, a psychiatrist and drug abuse researcher at Columbia University, who said many marijuana studies present a “chicken-and-egg” dilemma:
“It’s very possible that there’s something very different to begin with among teenagers who tend to get into trouble with marijuana or who become heavy users. They could have subtle emotional differences, perhaps some cognitive functioning differences.”
Most frightening is that adolescent marijuana use is associated with a two- fold increase in developing a psychiatric disorder, including schizophrenia, bipolar disorder, major depression, and substance-abuse disorders. Although there are many factors at play here, including individual genetics, numerous human and animal studies have shown that THC, the psychoactive component in cannabis, can enhance the risk of schizophrenia in brains that are already susceptible to it. This theory, that genetics coupled with early environmental factors such as cannabis use can trigger the onset of mental illness, is known as the “two-hit hypothesis.” Jorge Barossa-Aranda, Vice-President of medical research at Oasis of Hope Health Group, explains:
“The coexistence of an addictive and a psychiatric disorder is known as “dual pathology”… In a very recent study carried out in the mental health network and drug network of the Community of Madrid (Spain) it was observed that 76.5% (out of 837 patients, 353 had a diagnosis of cannabis abuse) of the cannabis addicts had a current dual disorder…Of those addicted to cannabis, 51% had a personality disorder…The presence of these mental disorders was significantly associated to a lower age at initiation of cannabis use.”
Fresh evidence from the University of Bristol shows that people who have a greater risk of developing schizophrenia are also more likely to try cannabis, suggesting that the drug may be used to self-medicate.
Teenagers, for the most, do not seem too concerned. In a recent survey from the National Institutes of Health, 60% of high school seniors say they think marijuana is safe, 6.5% report using it regularly, and 23% say they’ve used marijuana in the past month — more than those who used alcohol or smoked cigarettes. This marks a profound shift from 1993, when 30% viewed it as harmless and only 2.5% of students used it regularly. According to a report from PBS, experts are studying whether marijuana laws have shifted public perception, or vice versa.
The internet may also play a role. As Paul Armentano, director of the National Organization for the Reform of Marijuana Laws, told PBS: he “attributes the seismic shift in public opinion to the advent of the internet, which allowed people to anonymously access a wide range of scientific information on marijuana.”
At the same time, official public messaging seems to have backfired. Dr. Scheff, author of Coming Clean: Overcoming Addiction and Ending America’s Greatest Strategy, has said that “public education on marijuana has been misleading, and subsequently, lost credibility with students…Kids saw kids smoking pot and doing okay.”
In other words, by painting marijuana as either good or bad, safe or not safe, the national discourse around marijuana has been not only polarizing, but tone-deaf. We further quote the report from PBS, which offered some solutions:
“Sheff…cites the success of the truth campaign, which targeted cigarettes ads for manipulating kids into thinking smoking was cool. And the nuanced national discussion around safe alcohol use, leading to wider social awareness of how much an individual drinks and when it’s safe to drink. Armentano says educators and policymakers ought to focus on why alcohol and tobacco use has declined among teens and apply that lesson to marijuana.”
As we recently discussed in WILTW January 24, 2017, the essential question is not simply how kids are smoking today, but why. The answers may tell us something greater about our culture, about what we value and don’t. “There’s more stress, more anxiety, more alienation,”Scheff told PBS. As the push towards legalization accelerates, the risks of a mental health crisis warrant serious concern.
This article was originally published in “What I Learned This Week” on March 9, 2017. To subscribe to our weekly newsletter, visit 13D.com or find us on Twitter @WhatILearnedTW.
