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Kiwi families, communities, and especially our young people are already paying a heavy price for a culture that has grown too casual about and perhaps even normalised cannabis use. The 2020 referendum narrowly rejected legalising recreational use (50.7% against), reflecting the common-sense view of many Kiwis that normalising a mind-altering drug is not progress. Yet trends since then show why vigilance is needed.

The latest Massey University New Zealand Drug Trends Survey (NZDTS 2025) indicates that daily cannabis use among users has jumped from 39% in 2020 to 53% in 2025. Prices are falling, availability is higher than ever, and there is a shift toward vaping and edibles, making it easier and more discreet for young people to use. Medicinal cannabis prescriptions have exploded (over 380,000 products supplied in 2025), but this has blurred lines between “medical” and recreational use, with many citing medicinal reasons while patterns suggest broader normalisation.

Population data shows past-year cannabis use at around 15.6% of adults, with higher rates among Māori (33.4%) and young people. Weekly use remains a significant issue for tens of thousands of teens and young adults. This aligns with ongoing concerns in other countries about adolescent cannabis use and its impacts on the developing brain.

A wave of major new studies, led by the Adolescent Brain Cognitive Development (ABCD) Study—the largest long-term youth brain study in the United States—paints a consistent picture: cannabis use during the teenage years interferes with critical brain development, particularly in memory, thinking speed, and reward processing. It also significantly increases the risk of serious mental health disorders later in life. The ABCD findings (e.g., slower cognitive gains in users) do not stand alone. Several other major studies published or released around late 2025–early 2026 reinforce the same concerning patterns.

A recent systematic review published in Frontiers in Psychiatry (2026) examined 36 studies with over 8,400 participants. It found consistent evidence of dose-dependent brain changes in adolescents who use cannabis, such as decreased volumes in the prefrontal cortex and hippocampus/amygdala, faster cortical thinning, and white matter impairments. It also noted increased vulnerability to addiction and variable but concerning cognitive effects. Adolescent-onset use showed greater susceptibility than adult-onset use.

One of the largest US longitudinal studies on adolescent cannabis use and psychiatric disorders analysed medical records of nearly 463,000 adolescents (ages 13–17) in Northern California (study carried out by Kaiser Permanente). Teens who reported past-year cannabis use had roughly double the risk of later diagnosis with psychotic or bipolar disorders, plus significantly higher risks of depression and anxiety (adjusted hazard ratios around 1.2–2.2). Associations held after accounting for prior mental health issues and other substance use, with stronger effects in younger teens. The study positions cannabis as a risk factor (or exacerbating factor) for psychiatric disorders, not merely a result of pre-existing conditions. Authors emphasised prevention, public health messaging, and policy responses amid the expansion of legalisation.

In a 12-month longitudinal brain imaging study, regular cannabis users (adolescents and adults) showed declining activity in the ventral striatum (the brain’s key reward centre) when anticipating non-drug rewards. This dulling of natural motivational pathways might help explain the decrease in drive, focus, and enjoyment of daily pleasures with cannabis users.

Research from both cross-sectional and longitudinal studies (including ABCD) has shown that regular cannabis use during adolescence and young adulthood is associated with modest decreases in IQ (on the order of ~2 points in meta-analyses of frequent users), verbal memory, attention, processing speed, and certain executive functions. While some earlier debates highlighted temporary effects or lower-potency products, today’s high-THC products and the adolescent brain’s ongoing maturation (into the mid-20s) amplify concerns.

The effects of adolescent cannabis use can persist in some domains even after abstinence, though there is some individual variability and confounding factors (e.g., other substances, socioeconomic status). While not every user experiences severe outcomes, population-level data and dose-response patterns warrant attention from parents, educators, and policymakers, especially given the increasing availability and potency of these products.

The research is clear and consistent: high-THC cannabis today is not the “low-potency” weed of past generations. Combined with NZ’s existing youth mental health challenges, continuing down a path of liberalisation risks entrenching generational harm, poorer educational outcomes, fractured families, and higher welfare and justice costs.

Protecting our future generations is more important than ever in a world where the acceptance of drugs and their associated harms seems to be increasing, despite the growing evidence of their harms and impacts not just on individuals but on society at large. Whether it’s local trends or international evidence, they all demand that we heed the warnings and prioritise long-term societal and family well-being over short-term liberal experimentation. Parents, churches, communities, community leaders, and politicians have a responsibility to make it clear: for our young people, cannabis is not harmless recreation; it is a significant risk we cannot afford to continue to downplay or ignore.

*Written by FF staff writers*

A recent study out of the UC San Diego School of Medicine has found that teenagers who start using cannabis experience slower development in their thinking and memory abilities over time.

The study, published on April 20, 2026, in Neuropsychopharmacology, examined data from 11,036 participants in the Adolescent Brain Cognitive Development (ABCD) Study—the largest long-term research project on brain development in U.S. youth. Researchers followed children from ages 9–10 into ages 16–17, tracking both substance use and cognitive performance. They used a combination of self-reports and objective toxicological measures (urine, saliva, and hair samples) to better detect cannabis exposure.

Findings showed that, across a range of skills (including memory, language, and processing speed) teens who used cannabis exhibited slower gains (restricted developmental trajectories) over time compared to non-users. Interestingly, at younger ages, some future cannabis users performed as well as or slightly better than non-users. However, as they aged and began using cannabis, their cognitive development stalled relative to peers who continued to progress.

The study also examined cannabis components in a smaller subset with hair testing. Teens with evidence of tetrahydrocannabinol (THC) exposure (the main psychoactive component) showed more significant memory declines over time than non-users. In contrast, teens with evidence of cannabidiol (CBD) did not exhibit this pattern (though the CBD group was small).

“These results point to THC as a likely driver of the changes we’re seeing,” said lead researcher Natasha Wade. “It also highlights how complex cannabis products can be, especially since some products labelled as CBD may still contain THC.”

Despite the modest size of the differences, the findings are noteworthy during a period of rapid brain development: even small changes in memory, attention, or processing speed can influence school performance and daily life.

Despite the differences being modest in statistical terms, the real-world stakes are high. During a period of rapid and foundational brain development, even small deficits in memory, attention, or thinking speed can impair school performance, learning, decision-making, and long-term life outcomes.

The researchers rightly note that the study does not prove direct causation on its own, and other factors (environment, personality, genetics) may play a role. Yet the associations held strong even after adjusting for family background, mental health, other substance use, and prior cognitive performance. This is not isolated data—it adds to a large and growing body of evidence showing adolescence is a uniquely vulnerable window for cannabis harms.

These findings should serve as a loud wake-up call. Public health experts, parents, educators, and policymakers must be unequivocal: adolescents should not use cannabis. The developing brain is simply too precious and too sensitive to risk interference from THC. With today’s high-potency products widely available, the potential for harm is greater than ever.

As evidence from major studies such as ABCD emerges, it’s clear that the effects of cannabis, particularly during adolescence, are more significant than many acknowledge. The data is undeniable. Safeguarding the next generation requires taking this science seriously and acting on it.

*Written by FF staff writers*

Alongside chronic pain, mental health conditions are among the most common reasons people turn to marijuana for medical use. However, a comprehensive review of cannabis research spanning the past 45 years finds little to no high-quality data supporting its effectiveness for these medical conditions.

Published in the Lancet journal, the meta-analysis found cannabinoids (a type of medicinal cannabis) had no meaningful benefit or significant impact on primary outcomes for anxiety, PTSD, psychotic disorders (including schizophrenia), anorexia nervosa, OCD, opioid use disorder, cocaine use disorder, bipolar disorder, ADHD, and tobacco use disorder. To date, this is the largest and most comprehensive systematic review and meta-analysis of data from randomised control trials (RCTs) on the effectiveness and safety of cannabinoids for the treatment of mental disorders and SUDs. The team of researchers in Australia reviewed 54 trials involving 2,477 participants, considering a wide range of conditions, formulations and types of cannabinoids.

The study found that the use of medicinal cannabis for common psychiatric conditions like anxiety, PTSD, and depression was ineffective. Interestingly, they found it did have some impact (though small and the evidence was deemed low-quality by the study’s authors) on conditions like insomnia, autism and tic or Tourette’s syndrome. One of the study’s authors, Jack Wilson, a postdoctoral research fellow at the Matilda Centre for Research in Mental Health and Substance Use at the University of Sydney, says, “We clearly need to do more research on cannabis medicines.” “In the absence of evidence at this time, the routine use of medical cannabis products really should be rarely justified for the treatment of mental health disorders,” he told NPR.

He isn’t the only cannabis researcher echoing these sentiments. Ryan Vandrey, a professor of psychiatry and behavioural sciences at Johns Hopkins University School of Medicine who studies cannabis, says, “It’s embarrassing how little we have done in terms of data collection, given how widely this is available as a therapeutic”. Regarding the study, he says, “Though done well, a review of this nature invariably comes with major limitations. It collapses data across different products, doses, routes of administration, patient populations, and so on — and excludes findings from long-term observational studies and other sources of evidence. “So it can be challenging to draw firm conclusions, especially when there are not that many actual studies or patients being evaluated,” he says.

This study closely follows another substantial review, published earlier this month in JAMA Internal Medicine. That study adopted a broader methodological approach — including observational research and other study designs beyond randomised controlled trials — yet reached a similar conclusion: there is little convincing evidence that cannabinoids substantially treat mental health conditions. It also issued a caution regarding vulnerable populations, highlighting particular concerns for adolescents, young adults, individuals at risk of substance use disorders, and those living with bipolar disorder or psychotic conditions. This is not a new warning — the association between early cannabis use and increased risk of psychosis is among the more well-established findings in the field.

Whilst the research has technical limitations, like most research studies, its findings can’t be overlooked nor understated. The fact remains that in many countries where medicinal cannabis is loosely regulated, and its advocates are calling for even laxer controls (including NZ) due to the supposed benefits, the science states otherwise.

As the study’s authors noted, due to limited evidence of effectiveness and a higher risk of all-cause adverse outcomes, the routine use of these medicines for mental disorders and SUDs is rarely justified.  It is time for laws, policies, and even politicians to keep pace with the science.

*Written by Family First staff writers*

Legalising cannabis as a move aligned with history’s progress is beginning to crack, at least in the United States.

A referendum campaign is gaining momentum in Massachusetts to overturn the state’s 2016 legalisation of recreational cannabis. This comes amid new research indicating a rise in young cannabis users presenting at hospital emergency departments. This isn’t the only US state to psuh back against legalisation. Other US states such as Maine, Florida and North Dakota and South Dakota have shut down legalisation ballot initiatives, with Idaho set to vote on stronger cannabis prohibitions next year.

Even the US Congress, on a bipartisan basis, passed legislation quietly re-banning a type of cannabis that had been legal nationwide for nearly a decade. The nationwide ban on all kinds of THC comes into effect next year, meaning Americans will, for the first time since federal prohibition in 1937, have less access to cannabis than they previously did.

Since California legalised medical marijuana in 1996, momentum toward liberalisation has appeared relentless. Recreational marijuana is now legal in 24 states and Washington, D.C., with a further 15 states allowing medical use. Public support rose steadily from around 25 per cent in the late 20th century, reaching a majority in 2011 and peaking at 70 per cent in 2023—including majority support among Republicans. Political leaders and activists confidently declared the issue “settled” and “on the right side of history.

For years, cannabis legalisation was seen as inevitable. However, that trend is now showing signs of reversal, with a significant drop in Republican support for the first time since 2016, and even in public support. What once seemed to be an unstoppable cultural movement is showing signs of public reconsideration—suggesting that legalisation persisted not because it was wise or harmless, but because it was regarded as beyond debate.

Interestingly, most Americans neither use cannabis nor have a personal stake in the issue. A 2024 Pew poll shows support for recreational legalisation is about 15 points lower than in other surveys. A 2022 Emerson poll, funded by the anti-legalisation group Smart Approaches to Marijuana, found only 38% supporting the legalisation of “production, recreational use and sales, like in stores,” 18% supporting just decriminalisation of possession, and 30% advocating only for medical use. It seems that while many Americans support legal cannabis in theory, they often prefer it not to be present in their local communities.

For years, cannabis legalisation was presented as inevitable in New Zealand, following the same overseas script that framed reform as “progress” and resistance as outdated. By the time of the 2020 cannabis referendum, voters were told that legalisation was simply the next step on the right side of history.

New Zealanders disagreed. Despite heavy campaigning and cultural pressure, the public voted no—sending a clear message that the wellbeing of families, children, and communities mattered more than ideological momentum. That decision now looks increasingly prudent as overseas jurisdictions quietly confront the unintended consequences of liberalisation, from increased exposure for young people to growing concerns about mental health and community harm. Far from being left behind, New Zealand showed that careful restraint—grounded in protecting the vulnerable—still resonates when voters are trusted to weigh the real costs.

More Americans are realising that the promises of legalisation were overstated and its costs were underestimated. This was evident in the 2020 Cannabis referendum in New Zealand, where most voters saw through the facade and voted no to cannabis legalisation. That choice now seems increasingly wise as other countries quietly face the unintended effects of liberalisation, including greater risks for youth, mental health issues, and community damage. Rather than falling behind, New Zealand demonstrated that restraint—focused on safeguarding the vulnerable—remains powerful when voters are trusted to consider the true costs.

So as more US states consider banning what is widely recognised as a harmful drug, we welcome this shift in attitude and policymaking. It’s also encouraging to see international contexts recognise that legalisation isn’t the perfect solution it’s sometimes portrayed to be, and that prohibiting harmful drugs is becoming an increasingly accepted and normal response by governments and society.

*Written by Family First staff writers*

As the Green Party rehashes their campaign for legalising cannabis and decriminalising drugs, they continue to ignore the Science on the significant harms of cannabis use.  A new study published in the Addictive Behaviors Journal offers one of the most comprehensive analyses to date, examining how cannabis use affects youth aged 15 to 30, and the findings are disturbing and unfortunately unsurprising.

This systematic review and meta-analysis, a pinnacle of evidence-based research, analysed data from 36 studies, with 18 studies ultimately included in the final analysis, encompassing over 500,000 young people. The robustness, reduction of biases through structured methodology, and critical appraisal of systematic reviews and meta-analyses make it difficult to fault the findings from this type of research, apart from the self-identified limitations noted by the authors.

The researchers focused on four crucial mental health outcomes (depression, anxiety, suicide ideation and suicidal attempts) in relation to cannabis use, and the findings are sobering and staggering. They confirm what Family First has been warning about: the increasing harms from cannabis. The findings highlighted that regardless of age, gender and even other associated drug use, individuals who use cannabis face a:

• 28% higher risk of depression
• 58% higher risk of anxiety
• 64% higher risk of suicidal ideation 
• 80% higher risk of suicide attempts

The authors underscore a concerning trend: more studies are revealing that cannabis use in adolescent years is linked to subsequent depression in adult years. As frequency and dosage of cannabis use increase, so does the prevalence of depression.  This pattern seems to hold true for all mental health outcomes assessed in the study – that increased cannabis use often correlates with a higher prevalence of  mental health-related outcomes.

Whilst the study didn’t have a gender-specific focus in its analysis (due to most studies being mixed-gender studies), some evidence suggests that young women may be more vulnerable, especially to mood and anxiety disorders. Women with suicidal thoughts were also more likely to use cannabis as a form of self-medication, which often worsened their condition.

The findings further revealed that cannabis use beginning as early as age 15 is linked to long-term mental health impacts. THC—the psychoactive component of cannabis—interferes with brain signaling, emotional regulation, and cognitive function. Adolescents and young adults, who are in a critical stage of brain development, are particularly at risk, yet often overlooked in cannabis research.

As cannabis becomes more accessible and socially accepted, especially among young people, researchers are raising red flags about its devastating impact on the mental health of younger and future generations. The evidence is mounting and clear – cannabis use is not harmless. Legalisation and normalisation of cannabis use will only exacerbate the mental risks and impacts on our young people.

We must continue to resist efforts to legalise and decriminalise this drug, which carries long-term consequences not only for young people but for society as a whole.

**Written by Family First staff writers**

Link to study: https://www.sciencedirect.com/science/article/pii/S0306460325002977?via%3Dihub#s0095