The Patient Who Changed My Research Direction

I did not start my career planning to study cannabis. My early research focused on ADHD -- specifically, prescribing patterns for children with ADHD and the consequences of how we treat this disorder at a population level. That work led to a JAMA study on antipsychotic prescribing in ADHD youth that has been cited over 400 times, an NIH NIDA K12 award, and a research program centered on understanding how psychiatric medications are used -- and misused -- in young people.

But clinical practice has a way of redirecting your attention. Sometime around 2019, I started noticing a pattern in my clinic at Columbia. I was seeing more and more adolescents and young adults presenting with psychotic symptoms -- paranoia, disorganized thinking, hallucinations -- that were clearly connected to cannabis use. Not heavy, years-long use in many cases. Sometimes just a few months of regular vaping or dabbing.

These were not patients with prior psychiatric histories. They were high school students, college freshmen, kids who had been on trajectory until they were not. The common denominator was high-potency cannabis.

I remember one patient in particular -- a 17-year-old who had been an honors student and varsity athlete. He started vaping THC concentrates during his junior year. Within six months, he was hospitalized for a psychotic episode. When I met him, he was a shadow of the kid his parents described. He eventually recovered, but it took months, and he never fully returned to his prior level of functioning.

That case was not unique. I was seeing versions of it multiple times a month. And I realized the research I had been trained to do -- population-level epidemiology, health services research -- could be applied to a problem that was getting worse in real time.

The Gap Between Perception and Evidence

What struck me most was not just the clinical cases. It was the disconnect between what the public believed about cannabis and what I was seeing in the data and in my exam room.

The cultural narrative around cannabis had shifted dramatically. Legalization was spreading across states. Cannabis companies were marketing products with glossy branding and wellness language. Parents who had used marijuana in the 1980s and 1990s assumed it was the same substance their kids were using. The prevailing attitude was: "It's just weed. It's natural. It's safer than alcohol."

The problem is that the cannabis available today is not the cannabis of the 1990s. THC potency has gone from an average of about 4% to 15-25% in flower, with concentrates and vape cartridges reaching 80-90% THC. That is not a gradual increase -- it is a fundamentally different product. Calling both products "marijuana" is like calling beer and Everclear the same thing because they both contain alcohol.

And the data were accumulating: cannabis use was associated with psychosis risk, cognitive decline, impaired academic performance, worsening depression and anxiety, and cannabis use disorder in a significant minority of users. Daily use of high-potency products was linked to a 4-fold increase in psychosis risk. Yet public perception had not caught up.

I saw an opportunity -- and a responsibility -- to bridge that gap.

From ADHD Research to Cannabis

The transition was not as sharp as it might seem. ADHD and substance use are deeply intertwined. Adolescents with ADHD are at elevated risk for developing substance use disorders, including cannabis use disorder. Much of my ADHD research had already touched on substance use outcomes -- examining whether stimulant medications increase or decrease the risk of later substance problems.

What shifted was my primary focus. I went from studying ADHD treatment patterns to studying cannabis itself -- its composition, its accessibility, its effects on developing brains, and the regulatory environment that determines what ends up in consumers' hands.

This led to the Cannabis Access and Safety in New York (CASNY) study, which became the anchor of my research program. CASNY is a multi-phase project that examines how cannabis legalization has played out on the ground in New York City. We have looked at youth access (spoiler: it is disturbingly easy), product labeling (often inaccurate), and the chemical composition of products sold in licensed and unlicensed dispensaries (concerning).

The study has produced findings that I think are important for policy. We sent a 22-year-old research assistant as a secret shopper to visit cannabis retailers across NYC. Unlicensed outlets -- which vastly outnumber licensed ones -- rarely verified age. They sold cannabis alongside candy and energy drinks, used cartoon signage, and made it trivially easy for young people to purchase THC products. All licensed dispensaries checked ID at the door. Fewer than half of unlicensed shops bothered at any point during the purchase process.

What I See in Practice

I want to be clear about something: I am not anti-cannabis as a political position. I am a researcher and a clinician. My job is to follow the evidence, treat patients, and communicate what the data show.

What the data show -- and what I see every week in my practice -- is that cannabis is not benign for young people. The patients I treat include:

These are not abstract data points. They are people sitting in my office, and in many cases, the problems could have been prevented with better information, better regulation, and earlier intervention.

The PAWS Project: Building Something New

Research findings matter, but they are only part of the equation. The other part is building tools that translate evidence into clinical impact.

That is what led me to develop PAWS -- a digital therapeutic for cannabis use disorder that we are building in collaboration with Xuhai "Orson" Xu at Columbia's Department of Biomedical Informatics. PAWS uses AI and large language models to deliver behavioral health interventions to people struggling with cannabis use.

The motivation is simple: there are far more people who need treatment for cannabis use disorder than there are clinicians available to treat them. Cannabis use disorder affects roughly 30% of past-year cannabis users, yet most never receive any form of treatment. An AI-powered tool that can provide evidence-based support, available anytime, could reach patients that the current system cannot.

Building PAWS has been one of the most challenging and rewarding aspects of my work. It sits at the intersection of clinical psychiatry, AI, and digital health -- areas that do not always speak the same language. But I believe this kind of interdisciplinary work is where the field needs to go.

What Drives Me

People ask me sometimes why I chose this particular area of research. The answer is not complicated.

I am a child and adolescent psychiatrist. I care about young people. And right now, we are in the middle of a massive, uncontrolled natural experiment: we have legalized a psychoactive substance without adequate infrastructure to protect the most vulnerable population -- adolescents with developing brains.

The cannabis industry is growing. Products are getting stronger. Marketing is getting more sophisticated. And the kids I see in my office are paying the price.

My job as a researcher is to generate the evidence that policymakers, clinicians, and parents need to make informed decisions. My job as a clinician is to treat the patients in front of me. Both of those things require being honest about what we know and what we do not know.

What we know is clear enough: cannabis is not harmless for adolescents. The evidence supports that. And the evidence base is only going to get stronger, because my lab at Columbia is going to keep producing it.

Learn More About Our Research

Dr. Sultan's cannabis and mental health research program at Columbia University spans epidemiology, product safety, and digital therapeutics. Explore his published work or get in touch.

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