New research spanning three decades has revealed how experiences during childhood and adolescence significantly influence patterns of cannabis consumption well into adulthood. The French TEMPO cohort study, which followed 622 cannabis users over 30 years (1991-2021) from age 15 to 46, offers crucial insights for understanding and preventing sustained substance use.

Three Distinct Patterns Emerge

Researchers identified three clear trajectories amongst those who had tried cannabis during their teenage years. The majority—69.9%—showed declining consumption over time, naturally reducing their use as they matured. However, 13.7% demonstrated fluctuating consumption, characterised by an initial increase followed by a decrease around ages 27-30, whilst 16.4% exhibited persistent consumption throughout adulthood.

Understanding these childhood cannabis risk factors is essential for developing effective prevention strategies, particularly as the persistent use group began with the highest initial levels of consumption during adolescence.

Early Life Experiences That Matter

The study examined numerous early-life influences to determine which childhood experiences most strongly predicted long-term patterns. For those following the persistent consumption trajectory, three factors stood out prominently.

Academic difficulties emerged as a powerful predictor, with affected individuals 2.47 times more likely to maintain cannabis use into adulthood. This connection works both ways: struggling students may turn to substances as a coping mechanism, whilst cannabis use itself can impair thinking skills, attention and motivation—creating a cycle that perpetuates both academic challenges and continued use.

Early initiation proved particularly concerning. Young people who began using both tobacco and cannabis early were 3.07 times more likely to follow a persistent use path, whilst those who started cannabis early alone were 2.31 times more likely. The study defined early use as age 14 or younger for tobacco and age 16 or younger for cannabis. This finding underscores how the developing teenage brain responds differently to substances, with early exposure potentially changing the brain’s reward systems and increasing the risk of long-term dependency.

Gender also played a significant role, with males 3.66 times more likely to maintain persistent use patterns. This aligns with broader substance use trends, though the gap between males and females has been narrowing in recent years.

Family Environment and Fluctuating Use

For those showing fluctuating consumption patterns—the group that increased use initially before reducing it in their late twenties—family dynamics during childhood proved particularly influential as childhood cannabis risk factors.

Individuals who experienced parental conflict, stress or frequent parental absence before age 17 were 1.93 times more likely to follow this pattern. The family environment serves as a crucial foundation during formative years, and disruption to that stability appears to increase the risk of substance experimentation during adolescence and early adulthood.

Parental smoking also increased the likelihood of fluctuating use patterns significantly—children of smoking parents were 2.18 times more likely to follow this trajectory. Children naturally copy behaviours they observe at home, and parents who use substances—even legal ones like tobacco—may inadvertently signal acceptance of substance use to their children. Research shows that parental substance use not only directly influences children’s behaviour but also shapes their fundamental attitudes towards drugs and alcohol.

Additionally, males were 2.15 times more likely to follow the fluctuating pattern compared to females.

The eventual decline in use amongst this group around ages 27-30 likely reflects major life transitions: entering stable employment, forming committed relationships, pregnancy and parenthood. These milestones often prompt individuals to reassess their substance use, particularly when considering workplace responsibilities and family wellbeing.

Prevention Implications

These findings carry significant implications for prevention efforts. Rather than waiting until problems develop, identifying early cannabis use risk factors allows for targeted intervention during childhood and adolescence—when patterns are still forming.

Schools represent a crucial frontline for prevention. Supporting students who struggle academically, rather than viewing them solely through a disciplinary lens, may help prevent the turn to substances as a coping mechanism. Early screening for behavioural difficulties can identify at-risk young people before substance use begins.

Family support services prove equally vital. Families experiencing conflict, stress or instability need accessible resources to strengthen their functioning. When parents recognise how their own substance use—including seemingly benign behaviours like smoking—influences their children’s choices, they become powerful agents of prevention.

Understanding Childhood Cannabis Risk Factors for Better Outcomes

Education programmes must convey accurate information about cannabis risks, particularly concerning brain development. Many young people underestimate the dangers, believing cannabis to be relatively harmless. Correcting these misperceptions during the crucial window before first use can shift attitudes and delay or prevent initiation.

The study found that individuals born after 1980 were 37% less likely to engage in heavy cannabis use—suggesting that evolving social attitudes, policy changes and prevention programmes can make a difference. This offers hope that sustained prevention efforts targeted at early cannabis use risk factors can continue to shift patterns positively.

For young people who have already begun experimenting, early intervention remains critical. The research confirms that early, regular use dramatically increases the likelihood of persistent consumption. Catching use early and providing support to stop can alter the trajectory before patterns become entrenched.

The Broader Context

Whilst approximately 70% of adolescent cannabis users naturally reduce consumption as they mature, the 16.4% who maintain persistent use face significant long-term consequences. Extended cannabis consumption correlates with reduced educational attainment, lower income levels, higher unemployment rates, relationship difficulties, and both mental and physical health challenges.

The impact extends beyond individual users. Communities bear the costs through healthcare systems, lost productivity, and the ripple effects on families. Preventing persistent use patterns thus represents not just an individual health priority but a broader societal imperative.

Understanding that these patterns often originate in childhood experiences—academic struggles, family instability, parental substance use, early first use—shifts the focus towards prevention rather than dealing with problems after they emerge.

Looking Forward

This comprehensive research reinforces a fundamental principle: the earlier we can identify and address risk factors, the greater our chance of preventing long-term substance use patterns. Childhood and adolescence represent windows of both risk and opportunity.

At risk because developing brains respond differently to substances, early use can change brain connections, and formative experiences shape lifelong behaviours. Yet these years also offer opportunity—the chance to provide support before patterns become fixed, to strengthen protective factors, and to equip young people with skills and knowledge that serve them throughout life.

For parents, educators, healthcare providers and communities, the message is clear: attention to children’s wellbeing during formative years—their academic success, family stability, behavioural health and delay of substance initiation—represents our most powerful tool for preventing sustained cannabis use.

By identifying childhood cannabis risk factors early and responding with appropriate support, we can help ensure that the natural trajectory towards reduced use, followed by 70% in this study, becomes the norm rather than the exception. The goal isn’t simply preventing experimentation—adolescents will be curious—but preventing that experimentation from becoming a persistent pattern that compromises their health, opportunities and futures.

The three-decade span of this research demonstrates that choices and experiences during childhood genuinely matter for decades to come. That reality should inform how we prioritise prevention, early intervention and support for young people and families navigating these critical years.

(Source: WRD News) 

After more than two decades of mounting evidence and healthcare system strain, the World Health Organisation has formally recognised cannabis hyperemesis syndrome (CHS) in its International Classification of Diseases, marking a watershed moment in the acknowledgement of marijuana-related harms that industry propaganda has deliberately obscured.

The WHO published guidance in October 2025 establishing dedicated diagnostic codes that took effect on 1 October, which the US Centers for Disease Control and Prevention has adopted. The classification assigns CHS the code ICD-10-CM R11.16 and lists it as a synonym under ICD-11 code DD90.4. This formal classification enables physicians worldwide to properly identify, track, and study a condition that has plagued healthcare systems whilst being systematically downplayed by cannabis advocates.

The Smokescreen of Denial

Researchers first described the syndrome in a published case series in 2004, yet its formal recognition comes only now, over two decades later. Health experts argue this delay reflects a broader pattern of denial that pro-cannabis lobbying efforts have fuelled, consistently deflecting attention from emerging harms that marijuana use causes.

“This just one individual and health care system crippling outcome of cannabis use is unsustainable for any healthcare system, free or paid for,” noted one public health commentary in 2023. “The cannabis lobby and industry continue to deflect, as does the cannabis user, at this growing endemic and the outrageous expense it is incurring on non-drug using taxpayers.”

Medical literature first documented the paradoxical hyperemetic effects of marijuana in 2004, despite its well-known antiemetic properties. Even in subsequent years, experts emphasised that understanding the diagnostic criteria could reduce unnecessary investigations and inappropriate treatments. Yet formal recognition comes only now, with many attributing the delay to relentless cannabis propaganda that has bogged down fact and science in denial.

The Horror of ‘Scromiting’

Cannabis hyperemesis syndrome manifests as a dangerous condition affecting chronic cannabis users with severe nausea, repeated vomiting, abdominal pain, dehydration, weight loss, and in rare cases, heart rhythm problems, seizures, kidney failure, and death.

Patients suffer from what emergency room staff have termed “scromiting” (screaming and vomiting simultaneously due to extreme pain). The condition’s severity cannot be overstated: in 2024, a 22-year-old woman who had used cannabis since age 14 died after suffering from CHS for over three years. Her repeated vomiting episodes led to dangerously low potassium levels, ultimately triggering torsades de pointes, a fatal heart arrhythmia. Despite doctors restarting her heart, she had gone without oxygenated blood flow to her brain for over 30 minutes, resulting in irreversible damage. Doctors declared her brain dead four days later.

Emergency Departments Overwhelmed by Cannabis Hyperemesis Syndrome

A study published in JAMA Network Open in November 2025 revealed that CHS-related emergency room visits spiked approximately 650% from 2016 to their peak during the COVID-19 pandemic, particularly amongst those aged 18 to 35. The surge has remained elevated ever since.

Beatriz Carlini, a research associate professor at the University of Washington School of Medicine, emphasised the importance of the new diagnostic code: “It helps us count and monitor these cases. A new code for cannabis hyperemesis syndrome will supply important hard evidence on cannabis-adverse events, which physicians tell us is a growing problem.”

The dramatic increase in THC potency has likely contributed to rising rates. Today’s cannabis products often exceed 20% THC (some reaching over 90%) compared to just 5% in the 1990s. Researchers suggest isolation, stress, and increased access to these high-potency products during the pandemic accelerated the trend.

John Puls, a Florida-based psychotherapist and nationally certified addiction specialist, stated he has witnessed an “alarming” increase in marijuana hyperemesis, particularly amongst adolescents and young adults. “In my opinion, and the research also supports this, the increased rates of CHS are absolutely linked to high-potency cannabis,” he told media outlets.

Puls noted that the most common misconception claims the condition isn’t real, precisely the narrative cannabis advocates have promoted. “I believe the new diagnosis code is a significant step in the right direction,” he said.

Misdiagnosis and Patient Suffering

Until now, doctors struggled to diagnose cannabis hyperemesis syndrome because symptoms mimic food poisoning, stomach flu, and other gastrointestinal conditions. Some patients have gone months or years without answers, enduring repeated emergency room visits and expensive, unnecessary investigations.

A telltale sign is that sufferers often find relief only through long, hot showers (a temporary fix that scientists still don’t fully understand). However, the syndrome’s intermittent nature leads many users to believe episodes are flukes, continuing cannabis use only to become violently sick again.

Dr Chris Buresh, an emergency medicine specialist with UW Medicine, noted the paradox: “Some people say they’ve used cannabis without a problem for decades. But even small amounts can make these people start throwing up.”

Stopping cannabis use appears to be the only reliable cure. Typical nausea medications rarely help, forcing doctors to turn to stronger drugs or capsaicin cream. Yet many patients resist the diagnosis, and even those who accept it struggle to quit due to addiction.

One theory suggests heavy, long-term cannabis use overstimulates the body’s cannabinoid system, triggering the opposite of marijuana’s usual anti-nausea effect. Whilst cannabis can treat nausea in low doses (typically under 5% THC), the high-potency products now dominating the market appear to produce devastating consequences.

Financial Burden on Healthcare Systems

The healthcare costs that marijuana hyperemesis generates are staggering. Repeated emergency room visits, extensive diagnostic testing, hospital admissions, and futile treatment attempts place enormous strain on medical systems, with non-drug-using taxpayers ultimately bearing these costs.

Health commentators have described this burden as “unsustainable,” yet the cannabis industry continues to deflect responsibility whilst profiting from increasingly potent products.

As cannabis legalisation spreads and high-potency products proliferate, health experts expect cases to continue rising. The WHO’s formal recognition is anticipated to dramatically improve surveillance and help physicians spot trends earlier.

“My hope would be that with this new diagnosis code that CHS is more accurately diagnosed in an emergency room setting,” Puls said, adding that once someone experiences cannabis hyperemesis syndrome, they’re more likely to suffer it again.

Breaking Through the Propaganda

The two-decade delay in formal recognition highlights how effectively cannabis industry propaganda has obscured emerging harms. Whilst marijuana advocates have promoted the plant as harmless medicine, emergency departments have quietly dealt with the growing reality of “scromiting” patients and, in tragic cases, preventable deaths.

The WHO’s decision to add the condition to its diagnostic manual represents not just a medical milestone, but a public acknowledgement that the “smokescreen of denial” surrounding cannabis harms can no longer be sustained.

Understanding and acknowledging this syndrome is essential. Pursuing abstinence from cannabis leads to resolution of symptoms in the majority of patients, a simple truth that doctors may have recognised years earlier had relentless industry denial not bogged down science.

(Source: WRD News)

Devastating new research from the American College of Surgeons has exposed the lethal consequences of cannabis-impaired driving, revealing that more than 40% of drivers killed in car crashes between 2019 and 2024 in Ohio tested positive for high levels of THC.

Moreover, the findings, released last week, shatter the persistent myth that cannabis is a harmless substance with no fatal consequences. Indeed, the data adds to mounting evidence that driving under the influence of marijuana poses a severe and growing threat to road safety across the United States.

Federal Data Confirms Rising Threat of Drug-Impaired Driving

Significantly, the Ohio study aligns with multiple federal investigations documenting the escalating danger of cannabis-impaired driving on American roads. For instance, a 2022 study by the National Traffic Safety Board found marijuana present in approximately one-third of all motorists arrested for impaired driving nationwide.

Furthermore, research from the National Highway Traffic Safety Administration that same year revealed that over 25% of individuals killed or seriously injured in road accidents who tested positive for any drug had used marijuana. Remarkably, this figure exceeded the 23% who tested positive for alcohol, therefore signalling a fundamental shift in road safety threats.

Dangerous Misconceptions Fuel Cannabis-Impaired Driving Crisis

Perhaps most alarming is the widespread misunderstanding amongst cannabis users about the drug’s effects on driving ability. Consequently, a survey conducted by the Foundation for Traffic Safety earlier this year questioned 2,000 cannabis users, uncovering troubling attitudes towards drug-impaired driving.

Specifically, the research found that nearly 85% of cannabis users drive on the same day they consume marijuana. More concerningly, 81% believe that using cannabis either has no effect on their driving or actually improves it, a misconception with potentially fatal consequences.

In Virginia, for example, approximately 17% of residents admitted to driving whilst high multiple times in the previous month, according to the state Cannabis Control Authority. In other words, that equates to nearly one in five people regularly operating vehicles whilst under the influence. Disturbingly, 30% of respondents believe cannabis users are usually safe drivers.

State-Level Evidence Links Legalisation to Increased Fatalities

Meanwhile, data from states that have legalised recreational cannabis reveals a disturbing pattern. Notably, Washington state witnessed the proportion of drivers involved in fatal collisions who tested positive for THC double after legalisation, from approximately 9% on average in the five years before legalisation to 18% in the subsequent five years.

Similarly, Colorado, an early adopter of cannabis legalisation in 2014, experienced a near doubling of cannabis-related car crash fatalities between 2013 and 2020. Following legalisation in Oregon, Alaska, and California, car crash deaths increased by 22%, 20%, and 14% respectively.

As a result, these statistics suggest that legalisation contributes to increased cannabis-impaired driving incidents, thereby undermining road safety gains achieved through decades of public health initiatives.

The Erosion of Road Safety Culture

Over several decades, America developed a powerful cultural taboo against drink-driving, largely through sustained education and prevention campaigns by organisations such as Mothers Against Drunk Driving (MADD). Subsequently, these efforts fundamentally changed public attitudes and behaviours, saving countless lives.

However, the data indicates that cannabis legalisation has eroded similar taboos against drug-impaired driving. In particular, industry marketing campaigns promoting cannabis as medically beneficial and harmless have contributed to dangerous misperceptions about the drug’s effects on driving ability.

Additionally, the parallels with historic tobacco industry tactics are striking. Decades ago, tobacco companies paid medical professionals and scientists to promote cigarettes as beneficial to health. Today, the cannabis industry employs sophisticated marketing strategies that downplay or ignore the substance’s well-documented risks.

Broader Health Concerns Beyond Road Safety

Nevertheless, the dangers of cannabis extend well beyond impaired driving. Recent studies have linked marijuana use to serious cardiac events, damaged fertility in women, schizophrenia, and other severe mental health conditions. Furthermore, high-profile incidents involving individuals with documented cannabis use have highlighted the drug’s potential connection to violent behaviour.

Consequently, these broader health implications underscore the need for comprehensive approaches to cannabis prevention that address both immediate risks like cannabis-impaired driving and long-term health consequences.

Urgent Need for Prevention and Education

Clearly, the escalating crisis of drug-impaired driving demands immediate action. Therefore, robust awareness and prevention programmes are essential to educate the public, particularly younger drivers, about the deadly dangers of operating vehicles whilst under the influence of cannabis.

In addition, states must reconsider policies that have normalised cannabis use without adequate safeguards or public health protections. Indeed, the rush to legalisation has outpaced understanding of the substance’s risks, thus creating preventable tragedies on roads across the nation.

Moreover, federal authorities should prioritise research into cannabis-impaired driving, develop evidence-based prevention strategies, and support states in implementing effective enforcement and education measures. Ultimately, public health campaigns must counter industry messaging and establish clear understanding that cannabis significantly impairs driving ability.

In conclusion, the evidence is unequivocal: cannabis-impaired driving represents a growing threat to public safety. Only through comprehensive prevention efforts, honest public education, and evidence-based policy can this escalating crisis be addressed effectively.

(Source: WRD News)

A comprehensive decade-long study examining drug and alcohol presence in Victorian road crashes has revealed alarming trends, with methylamphetamine emerging as the most prevalent illicit substance detected in both injured and fatally injured drivers between 2010 and 2019.

The research, published in Injury Prevention and led by Monash University, represents the largest investigation of its kind conducted in Australia. Analysing data from 19,843 injured drivers and 1,596 fatalities, the findings paint a concerning picture of drug-impaired driving across Victoria’s roads.

Methylamphetamine Prevalence in Road Crashes Reaches Alarming Levels

The study found that methylamphetamine had the highest prevalence among Victorian drivers involved in crashes. Researchers detected the substance in 12.3% of fatalities and 9.1% of injured drivers, and these detections increased over time.

Taken together, these statistics underscore a growing public health and road safety challenge. In particular, methylamphetamine impairs cognitive function, reaction times, and decision-making abilities, all of which are critical for safe vehicle operation.

Multiple Substances Detected in Victorian Drivers

The research revealed that 16.8% of car drivers and motorcyclists tested positive for one or more drugs. Alcohol remained a significant factor, with 14% of crashes involving a blood alcohol concentration (BAC) at or exceeding 0.05%.

Cannabis (THC) emerged as another substance of concern, with detections rising amongst injured drivers until 2018. The study found THC detected in 8.1% of injured drivers and 15.2% of fatally injured drivers.

MDMA-positive driving decreased amongst injured drivers and remained stable at approximately 1% of fatalities throughout the study period.

Drug-Driving Patterns in Motorcyclists

Motorcyclists emerged as a particularly vulnerable population. Between 2015 and 2019, methylamphetamine was detected in 27.9% of motorcyclist fatalities, a figure substantially higher than the overall driver population. THC followed at 18.3%, with alcohol at or above 0.05% BAC detected in 14.2% of fatal motorcycle crashes. Similar but lower frequencies were observed amongst injured motorcyclists.

These elevated rates amongst motorcyclists warrant particular attention, as riders already face heightened vulnerability on roads due to reduced physical protection compared to enclosed vehicle occupants.

Alcohol Trends Show Mixed Results

The study documented a decline in alcohol detections (≥0.05% BAC) amongst fatalities. However, alcohol detections increased amongst injured motorcyclists and car drivers until plateauing in 2017. This mixed trend suggests that whilst fatal alcohol-related crashes may be decreasing, alcohol continues to contribute significantly to road trauma overall.

Demographics and Risk Factors

The research identified that there was a higher incidence of drug-positive driving amongst men and individuals aged between 25 and 59 years, alongside patterns of increasing drug use in motorcyclists.

Implications for Road Safety Prevention

The comprehensive data from the Victorian Institute of Forensic Medicine and Victoria Police provides robust evidence of persistent drug-impaired driving despite Victoria’s enhanced road safety measures.

Co-senior author Adjunct Associate Professor Dimitri Gerostamoulos from Monash University’s Department of Forensic Medicine and the Victorian Institute of Forensic Medicine stated that the findings confirm methylamphetamine, alcohol, and cannabis are the drugs that cause the most harm on Victorian roads.

The decade-long trends demonstrate that current prevention strategies require re-evaluation and strengthening. The study’s authors concluded that despite enhanced road safety measures in Victoria, drug-driving persists, indicating a need for revised prevention strategies targeting this growing issue.

Addressing the Drug-Driving Challenge

This research provides critical baseline data for policymakers, law enforcement, and public health officials working to reduce drug-driving incidents. The upward trajectory of methylamphetamine detections, combined with persistent alcohol involvement and rising cannabis presence, indicates that impaired driving prevention must remain a priority.

Understanding which substances most frequently impair drivers, and which demographic groups exhibit highest risk, enables targeted prevention initiatives. The particularly high rates of drug detection amongst motorcyclists suggest this group requires specialised attention in prevention messaging and enforcement strategies.

As Victoria continues developing its road safety framework, this evidence base highlights where authorities should concentrate prevention efforts to achieve meaningful reductions in drug and alcohol-related road trauma.

Read the full paper in Injury Prevention: https://injuryprevention.bmj.com/content/early/2025/01/17/ip-2024-045342

(Source: WRD News)

A groundbreaking study from McGill University has revealed alarming connections between early cannabis use and severe long-term health consequences, with researchers documenting substantially elevated risks for both mental and physical health problems amongst young users.

The research, published in JAMA Network Open, examined the relationship between the age at which individuals begin using marijuana and subsequent health outcomes. The findings paint a concerning picture of early cannabis use and its lasting impact on developing minds and bodies.

Staggering Mental and Physical Health Risks

According to the McGill University study, frequent marijuana consumption beginning before age 15 is associated with a 51% higher chance of developing mental health problems later in life. Even more striking, early cannabis use correlates with an 86% increased likelihood of physical health problems.

These figures represent some of the most compelling evidence to date regarding the dangers of teenage marijuana consumption. The researchers defined “frequent use” as consumption at least once monthly—a threshold that many would consider relatively moderate by today’s standards.

Youth Marijuana: A Gateway to Greater Harm

The study’s methodology raises important questions about the true extent of damage caused by early cannabis use. Since the research categorised monthly consumption as “frequent use,” the health implications for daily or near-daily users—particularly common amongst those who begin using during early adolescence—may be considerably more severe.

Research has consistently demonstrated that earlier initiation of marijuana typically leads to more frequent consumption patterns over time. This correlation suggests that the 51% and 86% increased risk figures from the McGill study may represent conservative estimates of the actual health burden associated with youth cannabis consumption amongst the heaviest consumers.

Teenage Brain Development Under Threat

The timing of cannabis initiation proves critical because the adolescent brain undergoes crucial developmental processes that continue into the mid-twenties. Early cannabis use disrupts these processes, potentially causing lasting alterations to brain structure and function.

Mental health problems linked to teenage marijuana consumption include increased rates of depression, anxiety disorders, psychosis, and schizophrenia. The developing brain’s heightened vulnerability to cannabis compounds explains why adolescent exposure carries such pronounced long-term consequences compared to adult-onset use.

Physical Health Consequences of Youth Cannabis Exposure

Whilst public discourse around marijuana often focuses on mental health impacts, the McGill research highlights equally concerning physical health ramifications. The 86% increased risk of physical health problems associated with early cannabis use encompasses respiratory issues, cardiovascular concerns, and immune system disruption.

Chronic cannabis consumption during adolescence has been linked to reduced lung function, increased susceptibility to respiratory infections, and potential long-term cardiovascular complications. These physical manifestations of teenage marijuana use often receive insufficient attention in policy debates around cannabis accessibility.

Policy Implications and Youth Protection

The study’s findings arrive at a crucial juncture in cannabis policy development across numerous jurisdictions. As legalisation and decriminalisation efforts advance globally, the McGill research underscores the imperative of robust youth protection measures.

Evidence demonstrating the severe health consequences of early cannabis use strengthens arguments for stringent age restrictions, comprehensive public education campaigns, and enhanced enforcement mechanisms to prevent teenage access to cannabis products.

The Cumulative Evidence Against Youth Use

The McGill University study joins a growing body of research documenting the particular dangers of starting marijuana before age 15. Longitudinal studies have repeatedly shown that individuals who begin using cannabis during their teenage years face elevated risks across multiple health domains compared to those who abstain or delay use until adulthood.

This accumulating evidence challenges narratives that minimise cannabis harms or suggest the substance poses limited risks to users. The data makes clear that early cannabis use carries profound, measurable consequences that extend far beyond the period of active consumption.

A Clear Message for Young People

With mental health problems rising 51% and physical health problems increasing 86% amongst those who begin frequent marijuana consumption before age 15, the scientific evidence delivers an unambiguous message: teenage cannabis use poses serious, long-term health risks.

The researchers’ findings emphasise that these elevated health risks stem from monthly use—a pattern many might not consider particularly intensive. For young people using cannabis more frequently, the health implications are likely substantially worse.

As communities grapple with evolving cannabis policies, protecting adolescents from early cannabis use must remain paramount. The McGill study provides compelling evidence that preventing youth marijuana consumption represents a critical public health priority with implications extending decades into users’ futures.

The complete study, authored by Martinez P, Chadi N, Castellanos-Ryan N, and colleagues, is available in JAMA Network Open (2025;8(10):e2539977. doi:10.1001/jamanetworkopen.2025.39977). (Source: WRD News)