It's becoming clear that adolescent brain is particularly vulnerable to cannabis, especially today's higher-potency products, which put teens at risk for impaired brain development; mental health issues, including psychosis; and cannabis use disorder (CUD).
That was the message delivered by Yasmin Hurd, PhD, director of the Addiction Institute at Mount Sinai in New York, during a May 6 press briefing at the American Psychiatric Association (APA) 2024 annual meeting.
"We're actually in historic times in that we now have highly concentrated, highly potent cannabis products that are administered in various routes," Hurd told reporters.
Tetrahydrocannabinol (THC) concentrations in cannabis products have increased over the years, from around 2%-4% to 15%-24% now, Hurd noted.
The impact of high-potency products and increased risk for CUD and mental health problems, particularly in adolescents, "must be taken seriously, especially in light of the current mental health crisis," Hurd and colleagues wrote in a commentary on the developmental trajectory of CUD published simultaneously in the American Journal of Psychiatry.
Dramatic Increase in Teen Cannabis Use
A recent study from Oregon Health & Science University showed that adolescent cannabis abuse in the United States has increased dramatically, by about 245%, since 2000.
"Drug abuse is often driven by what is in front of you," Nora Volkow, MD, director of the National Institute on Drug Abuse, noted in an interview with Medscape Medical News.
"Right now, cannabis is widely available. So, guess what? Cannabis becomes the drug that people take. Nicotine is much harder to get. It is regulated to a much greater extent than cannabis, so fewer teenagers are consuming nicotine than are consuming cannabis," Volkow said.
Cannabis exposure during neurodevelopment has the potential to alter the endocannabinoid system, which in turn, can affect the development of neural pathways that mediate reward; emotional regulation; and multiple cognitive domains including executive functioning and decision-making, learning, abstraction, and attention – all processes central to substance use disorder and other psychiatric disorders, Hurd told the briefing.
Volkow said that cannabis use in adolescence and young adulthood is "very concerning because that's also the age of risk for psychosis, particularly schizophrenia, with one study showing that use of cannabis in high doses can trigger psychotic episodes, particularly among young males."
Hurd noted that not all young people who use cannabis develop CUD, "but a significant number do," and large-scale studies have consistently reported two main factors associated with CUD risk.
The first is age, both for the onset and frequency of use at younger age. Those who start using cannabis before age 16 years are at the highest risk for CUD. The risk for CUD also increases significantly among youth who use cannabis at least weekly, with the highest prevalence among youth who use cannabis daily. One large study linked increased frequency of use with up to a 17-fold increased risk for CUD.
The second factor consistently associated with the risk for CUD is biologic sex, with CUD rates typically higher in male individuals.
Treatment Challenges
For young people who develop CUD, access to and uptake of treatment can be challenging.
"Given that the increased potency of cannabis and cannabinoid products is expected to increase CUD risk, it is disturbing that less than 10% of youth who meet the criteria for a substance use disorder, including CUD, receive treatment," Hurd and colleagues point out in their commentary.
Another challenge is that treatment strategies for CUD are currently limited and consist mainly of motivational enhancement and cognitive-behavioral therapies.
"Clearly new treatment strategies are needed to address the mounting challenge of CUD risk in teens and young adults," Hurd and colleagues wrote.
Summing up, Hurd told reporters, "We now know that most psychiatric disorders have a developmental origin, and the adolescent time period is a critical window for cannabis use disorder risk."
Yet, on a positive note, the "plasticity of the developing brain that makes it vulnerable to cannabis use disorder and psychiatric comorbidities also provides an opportunity for prevention and early intervention to change that trajectory," Hurd said.
The changing legal landscape of cannabis — the US Drug Enforcement Agency is moving forward with plans to move marijuana from a Schedule I to a Schedule III controlled substance under the Controlled Substance Act — makes addressing these risks all the timelier.
"As states vie to leverage tax dollars from the growing cannabis industry, a significant portion of such funds must be used for early intervention/prevention strategies to reduce the impact of cannabis on the developing brain," Hurd and colleagues wrote.
This research was supported in part by the National Institute on Drug Abuse and the National Institutes of Health. Hurd and Volkow have no relevant disclosures.
