Two new studies are shedding fresh light on why some young people start using cannabis while others do not. Research on teen brain and substance use shows the picture is less about individual willpower and more about environment. It comes down to who a young person spends time with, and how reachable they believe cannabis to be. Together, these findings matter for families, schools, and anyone working to protect young people from substances that carry real risks during development.

The Factors Behind Teen Cannabis Use: Friends and Perceived Access

Research published in the journal Addiction drew on data from the COMPASS study. This is a pan-Canadian longitudinal study tracking the health behaviours of secondary school students. Led by Marie-Pierre Sylvestre, a professor at the Université de Montréal’s School of Public Health, the analysis followed 1,768 students from 11 schools in Quebec between 2017 and 2019. All participants were non-users of cannabis at the outset.

The study examined two factors: having friends who use cannabis, and perceiving cannabis as easy to obtain. Neither factor operates alone. Having peers who use cannabis without believing the drug is accessible does not significantly multiply the risk of starting. But believing cannabis is within easy reach already raises the likelihood of initiation, even without friends who use it.

When both factors are present, the effect is considerably more pronounced. Adolescents who had friends who used cannabis and who perceived it as easy to obtain faced a 21.6 percentage point higher risk of initiating use compared with peers who had neither risk factor. Understanding teen brain and substance use helps explain why this combination is so potent during adolescence.

“Adolescents who had friends who used cannabis and who perceived cannabis as easy to obtain had the highest probability of initiating use,” said Sylvestre.

Why Perception of Access Matters So Much

One striking finding from the COMPASS research is that perception of access accounted for approximately 39% of the statistical link between having friends who use cannabis and going on to use it oneself. In practical terms, friends who use cannabis tend to make the substance feel closer and more obtainable. They may share products directly, make introductions, or simply normalise the idea that cannabis is easy to find.

This matters in the context of legalisation. Despite restrictions introduced under Canada’s Cannabis Act of 2018, more than three-quarters of students who held an opinion on the matter believed cannabis would be easy for them to obtain. Legal frameworks do not automatically translate into a perception of scarcity among young people.

The gap between what regulations intend and what young people actually experience remains wide.

What the Teen Brain and Substance Use Research Tells Us

Separate research from the University of Pittsburgh, published in Nature Communications, adds a biological dimension to the picture. Researchers led by Ashley Parr analysed data from more than 800 teenagers over up to nine years. They found that adolescents with lower baseline dopamine levels in the brain’s reward system were more likely to experiment with substances than those with higher dopamine levels.

Crucially, this appears to be a developmental dynamic rather than a fixed outcome. As teenagers aged and their dopamine systems matured, substance use tended to decline. Those who followed a pattern of early, temporary experimentation had significantly lower dopamine levels at the outset. Yet these levels increased steadily over time, coinciding with reduced use.

This does not make experimentation safe or inconsequential. It does help explain why certain young people are more drawn to risk-taking at particular points in development. It also helps explain why early adolescence is such a critical window for supportive intervention. The question for researchers and practitioners alike, as Parr notes, is not simply who experiments, but who goes on to escalate and continue into adulthood.

The Pittsburgh team also pointed to social media as a potential alternative reward-seeking outlet. Fast-paced digital environments may engage similar neurological pathways. Young people whose drive for stimulation and novelty is channelled into constructive activities, whether team sports, creative pursuits, or community involvement, may be less drawn toward adolescent cannabis use to fill that same need.

What This Means for Prevention

Taken together, these two bodies of research point toward environments as the primary arena for prevention. Adolescent cannabis use does not happen in a vacuum. It is shaped by who young people know, what they believe about the world around them, and what their brains are seeking at different stages of development.

The Université de Montréal researchers recommend strategies that work on both dimensions at once: the social environment and the perceived accessibility of cannabis. This means building genuine refusal skills in young people. It is not just about delivering information, but actively equipping them with the confidence to navigate peer situations. It also means developing strong relationships between adults and young people, and establishing clear, consistent norms around non-use within schools and communities.

“What works in prevention is equipping young people, not just talking to them about cannabis,” said Sylvestre. “Interactive activities led by peers or community practitioners have a much greater impact than a lecture or just transmitting information.”

For parents, the Pittsburgh findings offer a practical direction. Steering teenagers’ drive for rewarding, novel experiences toward positive social outlets helps channel the very impulses that might otherwise draw them toward substance use.

Prevention that works meets young people where they are. It understands the social and neurological forces at play. And it builds environments where cannabis simply does not feel like the next logical step.

Source: dbrecoveryresources