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Cannabis Legalization Needs Better Guardrails: A Researcher's Perspective

By Ryan S. Sultan, MD
Assistant Professor of Clinical Psychiatry, Columbia University
Director, Cannabis Safety and Mental Health Informatics
March 29, 2026

I Support Legalization. I Do Not Support What We Are Doing with It.

Let me be direct about where I stand: cannabis prohibition was a failed policy. It criminalized millions of people -- disproportionately Black and Latino Americans -- for using a substance that is, by most pharmacological measures, less dangerous than alcohol. The social justice case for legalization is strong and I agree with it.

I also study cannabis safety for a living. I direct the Cannabis Safety and Mental Health Informatics program at Columbia University. Our team has spent years examining what happens when cannabis enters the legal marketplace -- how it is sold, to whom, at what potency, with what safeguards, and with what accuracy in labeling.

What we have found is that the promise of legalization -- a regulated, safe, controlled market that protects consumers and reduces harm -- is not being fulfilled. Not because legalization was the wrong idea, but because we are implementing it with staggering inadequacy.

The Data: What Our CASNY Research Shows

Through our Cannabis Access and Safety in New York (CASNY) study, we sent a 22-year-old secret shopper into 37 cannabis stores -- both licensed and unlicensed -- across New York City. The findings were striking.

On youth access: Unlicensed retailers were significantly less likely to verify customer age. They sold cannabis at lower prices and used marketing strategies -- cartoon signage, placement alongside candy and energy drinks -- that are functionally targeting young people. In a city where illegal shops have far outnumbered legal ones, this represents a systematic failure of the consumer protection framework that legalization was supposed to create.

On product labeling: We analyzed 88 products from licensed and unlicensed retailers. Products from unlicensed shops were less likely to include basic information: identification as a cannabis product, THC potency, standard dose, expiration date, child safety warnings, or poison control information. They were more likely to feature child-oriented design elements like cartoons on the packaging.

On chemical safety: When we tested products in Columbia's mass-spectrometry laboratory, we found discrepancies between what retailers reported on their labels and what the products actually contained. This is not an academic finding. It means consumers are making dosing decisions based on unreliable information.

The THC Potency Arms Race

Here is a trend that should alarm anyone paying attention: the average THC concentration in cannabis has increased dramatically over the past several decades. What was once a plant with 3-5% THC is now routinely sold at 20-30% THC in flower form, with concentrates reaching 80-90% THC.

This is not the same drug that was used in the 1970s. The dose-response relationship matters. Higher potency cannabis is associated with:

• Greater risk of cannabis use disorder -- national data show that up to 30% of cannabis users develop a use disorder
• Increased risk of acute psychotic episodes
• Higher rates of cannabinoid hyperemesis syndrome (severe, cyclical vomiting)
• More pronounced cognitive impairment, particularly in adolescents and young adults
• Greater cardiovascular strain, including increased risk of stroke

Yet there are no federal limits on THC potency. Most states have no potency caps at all. The market is driven by consumer demand for higher-potency products, and the industry is happy to oblige. This is the equivalent of selling Everclear alongside beer and calling it a regulated alcohol market.

We do not let pharmaceutical companies sell medications at whatever dose they choose. We do not let alcohol manufacturers produce and sell products at unlimited proof without regulation. Why are we doing this with cannabis?

The Youth Access Failure

The central promise of legalization to parents, educators, and public health advocates was this: a regulated market will be harder for young people to access than the black market.

Our CASNY data suggest the opposite may be happening in New York. When unlicensed retailers dramatically outnumber licensed ones, when those unlicensed shops do not check identification, when they use youth-oriented marketing, and when they sell at lower prices -- the net effect is a market that may be more accessible to young people than what existed before legalization.

This matters because the developing brain is uniquely vulnerable:

• The prefrontal cortex -- responsible for judgment, impulse control, and decision-making -- does not fully mature until the mid-twenties
• Adolescent cannabis use is associated with persistent cognitive decline
• Early onset of regular cannabis use is a strong predictor of later cannabis use disorder
• There is a growing body of evidence linking heavy adolescent cannabis use to increased risk of psychotic disorders in genetically predisposed individuals

As a child and adolescent psychiatrist, I see the consequences of this failure in my clinical practice. The teenagers and young adults coming to me with cannabis-related problems are not using the low-potency plant their parents' generation experimented with. They are using high-potency concentrates, vape pens purchased from shops that never asked for their ID, and edibles in packaging that looks like it belongs in a candy aisle.

The Safety Testing Gap

Consider what happens when a pharmaceutical company wants to sell a product to American consumers. The drug goes through preclinical testing, Phase 1-3 clinical trials, FDA review, and post-market surveillance. The entire process takes years and costs billions. Every batch is tested. Every label is verified.

Now consider cannabis. It is consumed by tens of millions of Americans. It is inhaled, ingested, and applied topically. And it is subject to -- at best -- inconsistent state-level testing requirements that vary wildly in what they measure, how they measure it, and how they enforce compliance.

Our own research and the published literature have documented:

• Fatty acids linked to acute respiratory failure in vape products
• Pesticides exceeding legal limits in products from regulated markets
• Heavy metal contamination
• Inaccurate THC potency labeling -- sometimes dramatically so
• Inadequate characterization of how cannabinoids and terpenes transform during combustion and vaping, potentially producing additional carcinogens and respiratory irritants

The chemical composition of cannabis smoke and vapor has not been adequately studied. We do not know the full range of compounds consumers are inhaling. We have not accurately characterized how profiles of cannabinoids, terpenes, and other potentially harmful compounds vary across cannabis samples and modes of administration. This information is foundational for crafting effective safety regulations, and we do not have it.

What Other Countries Do Better

The United States is not the only country grappling with cannabis regulation, but it may be doing it the worst among developed nations that have legalized.

Canada's model is instructive. When Canada legalized cannabis federally in 2018, it implemented standardized packaging requirements (plain packaging with health warnings), strict marketing restrictions (no lifestyle advertising, no appeal to youth), and mandated THC limits on certain product categories. Is Canada's system perfect? No. But it starts from a position of public health priority rather than commercial permissiveness.

The United States, by contrast, has created the most commercially permissive cannabis market among legalized nations, with the least coordinated regulatory framework. The result is predictable: a market that prioritizes profit over safety.

Specific Policy Recommendations

Based on our CASNY research, the published literature, and my clinical experience, I recommend the following:

The Political Reality

I am aware that some of these recommendations will be unpopular with the cannabis industry, which has spent considerable resources opposing potency caps and marketing restrictions. I am also aware that some will be unpopular with advocates who view any regulation as a slippery slope back to prohibition.

Neither of these positions withstands scrutiny.

We regulate alcohol -- proof limits, age verification, marketing restrictions, manufacturing standards. We regulate tobacco -- ingredient disclosure, advertising bans, health warnings, age restrictions. We regulate pharmaceuticals exhaustively. The argument that cannabis should be exempt from consumer safety regulation is not a pro-freedom argument. It is a pro-negligence argument.

And the political maneuvering that keeps cannabis as Schedule I -- with some lawmakers citing outdated and debunked arguments that contradict the Department of Health and Human Services' own scientific recommendations -- is not protecting anyone. It is preventing the research we need to regulate intelligently.

The absence of stringent federal regulation is not an oversight. It is a ticking time bomb for consumer safety and public health.

What I Tell My Patients

In my clinical practice, I see patients across the age spectrum. When cannabis comes up -- and it comes up frequently -- I tell them the same thing I am writing here:

Cannabis is not inherently evil. It is not inherently safe, either. It is a psychoactive substance with real effects on the brain and body, and right now, the products available to you may not contain what their labels say they contain, may not have been tested for contaminants, and may be far more potent than you realize.

If you choose to use cannabis, buy from licensed retailers. Start with lower doses than you think you need, because the label may be wrong. Do not use high-potency concentrates unless you fully understand the risks. Keep cannabis products away from children. And if cannabis use is causing problems in your life -- anxiety, motivation, relationships, work -- seek help. Up to 30% of users develop a use disorder, and treatment works.

For parents: talk to your children about cannabis with the same honesty you would use for alcohol. The "just say no" approach failed. What works is accurate information about actual risks, delivered without hysteria but without minimization.

The Bottom Line

Cannabis legalization was the right policy decision. The way we are implementing it is not.

We have data showing that the current system fails to protect youth, fails to ensure product safety, fails to provide accurate consumer information, and fails to control the unlicensed market. We have evidence from other countries that better approaches exist. We have specific, implementable policy recommendations grounded in research.

What we lack is the political will to treat cannabis regulation with the seriousness it demands. That needs to change. Not because I am anti-cannabis -- I am not -- but because I am pro-consumer, pro-safety, and pro-evidence. And the evidence says we can do much better than this.

Frequently Asked Questions

Does Dr. Sultan support cannabis legalization?

Yes. I support legalization in principle, including the social justice rationale for ending criminalization. My concern is with implementation, not the policy direction. Current systems have critical failures in consumer safety, youth access prevention, product quality control, and regulatory enforcement that demand stronger guardrails and federal oversight.

What are the biggest problems with current cannabis regulation?

The biggest problems include: the proliferation of unlicensed retailers that outnumber legal shops in markets like New York, inadequate age verification allowing youth access, unreliable product labeling with discrepancies between labeled and actual THC content, insufficient contaminant testing, a THC potency arms race with no federal limits, and fragmented state-by-state regulation without federal coordination.

What cannabis policy changes does Dr. Sultan recommend?

I recommend potency caps on THC content, enforced age verification with meaningful penalties, mandatory independent lab testing for all products, restrictions on youth-oriented marketing and packaging, standardized federal labeling requirements, investment in cannabis safety research, removal of Schedule I research barriers, and establishment of a federal oversight body coordinating with state agencies.

How do other countries regulate cannabis better?

Canada implemented federal regulation with standardized testing, plain packaging requirements, strict marketing restrictions, and THC content limits on edibles. Uruguay established a government-controlled supply chain with price controls. The Netherlands uses a licensed coffeeshop model with purchasing limits. These approaches prioritize public health alongside legal access, rather than treating cannabis as a purely commercial enterprise.

Further Reading

• Cannabis Research Hub
• Cannabis Legalization Impact
• Cannabis Product Safety: FDA Research
• Teen Cannabis Use
• The CASNY Study