Marijuana and other drugs are not as dangerous as laws written half a century ago say they are, according to a new scientific review.

Since the passage of the Controlled Substances Act (CSA) in 1970, U.S. drug laws have been dictated by rigid categories that supposedly reflect the dangers posed by different substances—but the new study suggests that “drug policy contradicts expert assessments of drug harms” both in America and across the world.

The results indicate that governments’ legal rankings for substances bear little resemblance to what experts actually know about which drugs cause the most harm—something that cannabis consumers and much of the general public have long recognized.

Marijuana, for example, has been listed as a Schedule I drug in the U.S. for decades. While President Donald Trump signed an executive order directing the attorney general to expeditiously complete the process of moving cannabis to a Schedule III substance last month, that has not yet occurred.

In the new paper published in the December 2025 issue of Harm Reduction Journal, a multidisciplinary panel of U.S. researchers, clinicians and people with lived experience of substance use found that federal drug policy is “poorly aligned with scientific evidence” and often contradicts expert assessments of risk.

To reach their conclusions, the researchers adapted a method known as multi-criteria decision analysis. Seventeen experts evaluated 19 commonly used drugs across 18 categories of harm, ranging from overdose death and long-term health damage to family disruption, crime and economic cost. Each drug was scored and weighted to produce an overall harm ranking.

The study—titled “US drug policy does not align with experts’ rankings of drug harms: a multi-criteria decision analysis”—also found that nearly all drugs were more harmful to the people who use them than to others, a result with significant policy implications. “An array of harm reduction strategies should be considered,” the authors argue, noting that punitive approaches have coincided with rising overdose deaths rather than declines in use.

The findings arrive at a moment when federal and state officials are reconsidering long-standing approaches to drug regulation, sentencing and public health response.

“For example, cannabis was rated as less harmful than its Schedule I status suggests.”

By placing cannabis in the most restrictive legal category—while ranking fentanyl lower in Schedule II and leaving alcohol outside the federal drug scheduling system entirely—U.S. policy has created a framework that the authors say no longer reflects either scientific consensus or actual risk to the population.

“Resources should be focused on health and wellness, not on incarceration,” they wrote.

Taken together, the study paints a picture of a drug policy frozen in time—one that treats substances like cannabis and psilocybin as major threats while failing to adequately respond to the substances doing the greatest damage. As fentanyl deaths climb and alcohol-related harms persist, the authors suggest that aligning law with evidence is no longer just an academic concern, but a public health imperative.

“Psilocybin and cannabis are associated with less harm than many other drugs and with potential medicinal benefits but people who use them remain subject to punishment in many jurisdictions.”

The researchers argue that evidence-based scheduling could support a shift away from punitive enforcement and toward targeted harm reduction, expanded treatment access and public health interventions, particularly for fentanyl and alcohol.

Noting that “fentanyl was deemed the most harmful drug,” they point to evidence supporting naloxone distribution, fentanyl test strips and supervised consumption sites.

Calling for further examination, the authors write that the research “provides a useful starting point for future work in the U.S. that could account for additional drugs, drug benefits, vulnerable subpopulations (e.g., youth), and various methods of use and routes of ingestion.”

“Collectively, this work can be used to advance scientific debate about the best ways to reduce harms to people who use drugs and to redress societal impacts at the same time.”

The study comes on the heels of the Trump administration backing away from a prior federal recommendation to limit alcohol consumption to specific amounts, even as marijuana remains federally criminalized and more Americans are choosing cannabis for personal health reasons.

More changes are also on the horizon. President Trump signed a bill into law last year containing provisions that would remove barriers to conducting research into the risks and benefits of marijuana, psychedelics and other Schedule I drugs.