Ask Dr. Litinas: What science actually says about cannabis—and what we still don’t know

MICHIGAN—More Michiganders than ever are turning to cannabis for wellness and relief. But even with medical and recreational access, stigma surrounding the plant still lingers—especially when it comes to understanding what cannabis can actually do for our health.

One of the biggest obstacles to advancing cannabis science in the US is the fact that it’s still classified as a Schedule I substance by the Drug Enforcement Administration. This means cannabis is considered to have a high potential for abuse, with no accepted medical use.

This classification places cannabis in the same category as substances like heroin and has made it incredibly difficult for researchers to study cannabis in meaningful ways. 

Despite that barrier, a major milestone in cannabis science was reached in 2017 when the National Academies of Sciences, Engineering, and Medicine (NASEM) released the most comprehensive review of cannabis research ever conducted. The report, titled The Health Effects of Cannabis and Cannabinoids, analyzed over 10,000 peer-reviewed studies to assess what science truly knows about cannabis—and where the gaps still remain.

Although more research has been published since then, this report remains the most credible and large-scale scientific meta-analysis on cannabis to date. And as a medical cannabis expert, two major takeaways stood out to me: Cannabis is effective for treating chronic pain, chemotherapy-induced nausea and vomiting, and spasticity in multiple sclerosis. And for nearly every other area of medicine, we need more high-quality research.

What did the report find?

The NASEM report didn’t suggest cannabis is a cure-all. But it also didn’t ignore the growing scientific evidence that cannabis has legitimate therapeutic benefits.

That includes strong evidence that supports cannabis use for:

• Chronic pain in adults—one of the most common reasons people use cannabis. The report confirmed it can be effective, especially when other treatments fall short.
• Nausea and vomiting from chemotherapy—where cannabis-based medications significantly reduce these side effects in cancer patients.
• Spasticity in multiple sclerosis—where cannabis can reduce muscle stiffness and spasms in people living with MS.

It also showed moderate to limited evidence for:

• Sleep issues—certain cannabis products appear to help with falling and staying asleep.
• PTSD and anxiety—particularly with CBD, early findings are promising but more studies are needed.
• Appetite stimulation—especially relevant for people with HIV/AIDS or undergoing cancer treatment.

Why don’t we know more?

Importantly, the report didn’t really shed any new light on the long-term effects of cannabis on heart health, the impact of cannabis use during pregnancy, or the relationship between cannabis use and mental health disorders in people who are genetically predisposed.

The report was also clear: Legal barriers are stifling cannabis research.

Because cannabis remains a federally illegal substance, scientists face major hurdles—from lack of funding, to limited access to quality cannabis, to delays in getting research approved. Until those restrictions are lifted, progress will continue to lag behind public use.

Why does this matter for Michigan?

Cannabis is legal and widely used in Michigan—but our public health systems and clinical practices haven’t caught up to the science. Patients, caregivers, and even physicians often lack clear, evidence-based guidance. And when reliable information is hard to find, people are forced to rely on word of mouth or trial and error.

This is where the 2017 NASEM report still holds enormous value. It gives us a scientifically sound foundation—one that policymakers, clinicians, and consumers alike can build upon.

As someone who has worked at the intersection of medicine and cannabis for over a decade, I’ve seen firsthand how powerful this plant can be—and how misunderstood it still is.

The NASEM report marked a turning point. It gave the medical community and the public a clear-eyed look at what cannabis can (and can’t) do. Eight years later, it’s time we make full use of that knowledge—and push for the research still needed.

Let’s treat cannabis like any other medicine: with respect, responsibility, and a commitment to evidence. Whether you’re a patient, a provider, or a policymaker, the path forward should be grounded in science—not stigma.

Ask Dr. Litinas is a column that publishes twice monthly as part of The MichiGanja Report—our free, weekly newsletter about all things marijuana. Click here to sign up.

READ MORE: Why your cannabis deserves better than a Ziploc bag

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