By Dr. Rachel Docekal, MBA, Ed.D. – CEO, Hanley Foundation
Adolescent cannabis use has been linked to a significantly higher risk of mental health disorders in young adulthood. A large study published in JAMA Health Forum found that teens who reported cannabis use had twice the risk of developing psychotic or bipolar disorders, a 34% higher risk of depression, and a 24% higher risk of anxiety compared with non-users. Researchers emphasize that because the adolescent brain is still developing, exposure to THC during these years may increase vulnerability to psychiatric conditions later in life.
Over the past decade, conversations around cannabis have shifted dramatically. As legalization expands across the country, many people assume cannabis is relatively harmless, especially when compared to other substances. But emerging research tells a much more complicated story, particularly when it comes to young people.
Before looking at the research, it is important to understand what we mean when we talk about cannabis today. The term “cannabis-derived substances” refers to chemicals and compounds that come from the cannabis plant, including Cannabis sativa, Cannabis indica, and hybrid varieties. These substances can produce psychoactive effects, meaning they alter how a person thinks, feels, or experiences reality by acting on the brain and central nervous system. Simply put, cannabis can change the way the brain processes mood, perception, thoughts, and behavior.
Cannabis also exists in far more forms than many parents realize. While adults may think of cannabis simply as marijuana, today’s marketplace includes a growing number of products and chemical variants that young people may encounter in vapes, edibles, and other products. These include compounds such as:
- Delta-8, Delta-9, and Delta-10 THC
- THC-O, a semi-synthetic cannabinoid derived from THC that is often marketed as more potent
- THC-P (tetrahydrocannabiphorol), a naturally occurring cannabinoid that may be significantly stronger than Delta-9
- THC-V (tetrahydrocannabivarin), which can produce different, sometimes more stimulating effects
- CBG (cannabigerol), sometimes called the “mother cannabinoid” because other cannabinoids develop from it
- CBN (cannabinol), a compound that forms as THC breaks down, and is often marketed in sleep products
- HHC (hexahydrocannabinol) and HHC-P, chemically altered THC analogs commonly sold in vape and gummy products
The expanding number of cannabis compounds and high-potency products has made today’s cannabis landscape far more complex than many people realize. Before diving into the research, it is also important to share what we see every day in our work at Hanley Foundation. Families often come to us reporting sudden, frightening changes in their children’s behavior. They say things like:
- “They suddenly became extremely paranoid.”
- “They were hearing voices.”
- “They seemed disconnected from reality.”
In a number of cases, the young person left for college and returned home during a school break, exhibiting symptoms consistent with cannabis-induced psychosis. These experiences are not isolated.
What a New National Study Reveals About Teen Cannabis Use
A large new study published in JAMA Health Forum highlights a concerning reality: adolescent cannabis use is associated with a significantly increased risk of developing psychiatric disorders by young adulthood. For parents, educators, and policymakers, these findings reinforce the urgent need for stronger prevention efforts and honest conversations with youth.
The study followed more than 400,000 adolescents ages 13 to 17 who were screened for cannabis use during routine pediatric visits between 2016 and 2023. Researchers tracked participants through age 25 using electronic health records to identify new diagnoses of mental health conditions. The findings were striking.
Adolescents who reported using cannabis within the past year faced substantially higher risks of developing several psychiatric disorders compared to those who did not use cannabis. Researchers found that adolescents who used cannabis had:
- Twice the risk of developing psychotic disorders or bipolar disorder
- A 34% higher risk of developing depressive disorders
- A 24% higher risk of developing anxiety disorders
Importantly, these associations remained significant even after adjusting for factors such as socioeconomic status, alcohol use, other substance use, and prior mental health diagnoses. During the study period, researchers identified more than 4,000 new diagnoses of psychotic or bipolar disorders, over 62,000 new cases of depression, and more than 73,000 new anxiety diagnoses among participants. While the study does not claim cannabis alone causes these conditions, the findings strongly suggest that adolescent cannabis use is a meaningful risk factor for developing mental health disorders later in life.
Why the Adolescent Brain Is More Vulnerable to THC
The adolescent brain is still developing, especially the regions responsible for decision-making, emotional regulation, and impulse control. During this critical period, exposure to psychoactive substances can disrupt neural development and alter the brain’s reward and stress systems.
THC, the primary psychoactive component in cannabis, interacts with the brain’s endocannabinoid system, which plays a key role in mood regulation, memory, and cognitive function. Repeated exposure to THC during adolescence may interfere with these processes in ways that increase vulnerability to psychiatric conditions.
This risk is especially concerning given the dramatic increase in THC potency in modern cannabis products. Today’s cannabis can contain significantly higher concentrations of THC than products available even a decade ago.
How Hanley Foundation Is Working to Prevent Youth Substance Use
At Hanley Foundation, we often say the most effective addiction treatment is prevention. Studies like this reinforce why early education and prevention programs are so critical. When young people delay their first use of substances, their likelihood of developing substance use disorders and related mental health challenges drops dramatically. That is why Hanley Foundation’s prevention programs reach hundreds of thousands of students each year, equipping them with the knowledge and resilience needed to make healthy decisions. Parents also play a powerful role in prevention. Open, honest conversations about substances, combined with clear expectations and supportive relationships, can significantly reduce risk.
What Parents and Educators Should Know About Prevention
While these findings may sound alarming, they also present an opportunity for proactive engagement.
Families can help protect young people by:
- Starting conversations early about substance use and mental health
- Providing clear guidance and expectations around drug and alcohol use
- Modeling healthy coping strategies for stress and emotional challenges
- Seeking professional help early if mental health concerns arise
Most importantly, we must continue to replace stigma with education. Young people deserve accurate information about the risks associated with substance use so they can make informed decisions about their health and future.
A Call for Awareness as Cannabis Use Becomes More Common
As cannabis policies evolve across the United States, public health messaging must keep pace with scientific evidence. Legalization does not mean harmlessness, particularly for developing brains. The findings from this large national study serve as a reminder that youth exposure to cannabis carries real mental health risks, and that prevention, education, and early intervention remain essential tools in protecting the next generation. At Hanley Foundation, we remain committed to providing families, schools, and communities with the resources needed to prevent addiction before it begins and support healing when it occurs. Because when it comes to our children’s mental health, awareness and action can change the trajectory of a lifetime.
