By Russell R. Barksdale, Jr. and Andrew J. Gerber
Much attention has been directed toward involuntary health risks—microplastics in drinking water, fluoride level disputes, preservative debates, and the ongoing opioid epidemic. These concerns are warranted: exposures can lead to outcomes ranging from undetectable to life-threatening. In recent years, synthetic opioids such as nitazenes, more potent than heroin and in some cases even fentanyl, have emerged in Europe.
Their concealability highlights a broader public health dilemma: the risks of increasing potency for substances in circulation.
Cannabis now belongs in that conversation. While fentanyl and nitazenes represent immediate lethality, cannabis poses a slower but no less consequential threat particularly to adolescents and young adults. The drug itself has fundamentally changed. In the 1970s, marijuana contained 2–4% THC, its psychoactive compound.
Today, standard cannabis products average 15–20% THC, with concentrated forms such as waxes, oils, and edibles reaching 60–90%. What many historically recall as a mild social drug is now a highly engineered, far more potent substance.
This shift matters most during adolescence, a critical window for brain development.
While the brain stops growing in size by early adolescence, it continues to undergo essential fine-tuning through the mid-20s. The prefrontal cortex responsible for judgment, impulse control, planning, and prioritization is one of the last regions to fully mature. Cannabis exposure during this time disrupts pruning, white-matter development, and synaptic connectivity, potentially altering the trajectory of cognitive and emotional health for life.
Neuroscience is sounding alarms. A major longitudinal neuroimaging study found that cannabis use from mid- to late adolescence accelerated cortical thinning in the prefrontal cortex, even after adjusting for alcohol and nicotine. Additional human and animal studies link high-potency THC exposure in adolescence to impaired synaptic pruning, altered neurotransmitter function, neuroinflammation, and long-lasting changes in brain connectivity. Noteworthy, these effects are not replicated when exposure occurs in adulthood, underscoring the vulnerability of the adolescent brain.
Clinical and epidemiological findings are consistent. Decades of imaging reveal that young cannabis users experience reduced cerebral blood flow, delayed maturation, and increased risks of anxiety, depression, and psychosis. Adolescents who use cannabis may be more than eleven times more likely to be diagnosed with a psychotic disorder than their non-using peers. Academic decline, diminished IQ, impaired memory, and heightened susceptibility to other addictions are not rare outcomes but increasingly documented consequences.
And yet, amid dispensaries, billboards, and social media influencers, cannabis has been normalized as harmless or even therapeutic. The cultural familiarity over the decades of a “mild joint” obscures the reality; today’s cannabis is not the same drug. What was once a relatively low-potency experiment of the 1970s has become a high-intensity neuroactive exposure in 2025.
This is not a call for prohibition or moral character, but for open discussion, and honest research. Parents, educators, pediatricians, and policymakers owe young people evidence-based clarity, not complacency due to historical perspectives. Longitudinal studies that track brain health across the lifespan are urgently required. Education campaigns should make clear that while cannabis may have a place in adult life, adolescent exposure to high-potency products carries real and lasting risks.
We are at a crossroads. On one side rests the narrative of cannabis as benign, medicinal, and socially accepted. On the other is the growing body of science that reveals its neurotoxic potential, magnified by unprecedented potency, and its gateway to increasingly addictive substances. Which story we elevate will shape public health for decades to come.
If we demand water free of microplastics and food uncontaminated by endocrine disruptors, consistency and a fair and balanced perspective demands we also confront the neurodevelopmental risks of high-potency cannabis. Protecting young brains requires vigilance, transparency, and the courage to prioritize science over cultural convenience.
Our responsibility should be clear. It is to ensure that a generation navigating adolescence and early adulthood does so with their futures intact, not compromised by a drug that has quietly, but profoundly, transformed.
Russell R. Barksdale, Jr., PHD, MPA/MHA, FACHE, President and CEO, Waveny
LifeCare Network & Andrew J. Gerber, MD, PH.D., President and Medical Director, Silver Hill Hospital
