Medical Marijuana Availability Improves Mental Health In Older People, Research Finds

Medical marijuana being legally available “improved self-reported mental health among people aged 65 years and older,” according to a new study.

Among adults overall, “medical cannabis availability was not associated with self-reported poor mental health,” it adds. “Collectively, these results suggest medical cannabis availability has limited mental health effects on the population at large, with considerable mental health benefits for older adults.”

For people 65 and older, authors noted that living within 30 minutes of a dispensary “decreased the probability having a poor mental health day in the past month by about 10 percent,” which they point out was “a 3.5 percentage point decrease from an original probability of roughly 36 percent.”

“What may explain our finding that medical cannabis availability improves the self-reported mental health of people aged 65 and above? Likely pain relief,” the research brief from authors at the libertarian Cato Institute says. “Cannabis is a good treatment for chronic pain caused by nerve disease (neuropathy)—the most common justification for medical cannabis and a common chronic condition among older adults.”

The study used geographic data to” estimate medical cannabis dispensary availability’s effects on self-reported mental health in New York state from 2011 through 2021 using a two-stage difference-in-differences approach to minimize bias introduced from the staggered opening of dispensaries,” the paper says.

“Medical cannabis availability reduced past-month self-reported poor mental health days by nearly 10%—3.37 percentage points—among adults 65 and above.”

Researchers said their findings about the importance of dispensary locations should be heeded by legislators and other policymakers. “This is an important consideration for state regulators considering medical and recreational cannabis legalization,” they wrote, “and how to approach the proliferation of nondispensary businesses selling close cannabis substitutes, such as Delta 8, THCP, and THCA.”

Nevertheless, the Cato brief prominently features concerns that the broader proliferation of cannabis legalization and use is happening while science still knows too little about the effects of using marijuana.

“Our findings also suggest there is an urgent need to learn more about how cannabis use affects older adults. The federal government has heavily restricted clinical research involving cannabis for decades,” it says. “President Biden reduced many of these restrictions by signing the Medical Marijuana and Cannabidiol Research Expansion Act into law in December 2022; however, clinical evidence on the health effects of cannabis will likely remain limited for years to come.”

The Cato Institute’s research brief, posted on the organization’s website earlier this month, is based on a working paper from the same authors that was published in May by the National Bureau of Economic Research.

“Pain relief is the likely mechanism through which medical cannabis availability reduces poor mental health days among older adults.”

The two institutions frame top-level findings from the research in notably different ways, with Cato’s opening paragraph emphasizing the risks and dangers of cannabis use and the National Bureau of Economic Research emphasizing the “positive health impacts for older populations.”

Cato Institute:

Cannabis use across the United States continues to rise. Almost 40 states have enacted laws permitting medical cannabis use. Approximately 62 million Americans—which constitutes 22 percent of Americans aged 12 years and older—used cannabis in 2022, up from 11 percent in 2010. However, there is minimal published research on the effects of cannabis on mental health. It may exacerbate depression and other mood disorders; alternatively, it is promoted and consumed as a wellness product to treat these mental health conditions. Approximately 50 percent of medical cannabis consumers use it to treat anxiety, and 34 percent use it to treat depression. In addition to the sharp increases in cannabis use and contradicting evidence of its effects, a rapidly worsening mental health crisis—exacerbated by the COVID-19 pandemic—amplifies the need to understand how the availability of medical cannabis affects mental health.

National Bureau of Economic Research:

Evidence on cannabis legalization’s effects on mental health remains scarce, despite both rapid increases in cannabis use and an ongoing mental health crisis in the United States. We use granular geographic data to estimate medical cannabis dispensary availability’s effects on self-reported mental health in New York state from 2011 through 2021 using a two-stage difference-in-differences approach to minimize bias introduced from the staggered opening of dispensaries. Our findings rule out that medical cannabis availability had negative effects on mental health for the adult population overall. We also find that medical cannabis availability reduced past-month self-reported poor mental health days by nearly 10%—3.37 percentage points—among adults 65 and above. These results suggest medical cannabis access has positive health impacts for older populations, likely through pain relief.

To be sure, marijuana use by older adults has risen sharply, nearly doubling in over the course of the past three years, according to a recent study supported by AARP. Most 50 and older said they use cannabis to relieve pain, help with sleep, improve mental health and achieve other benefits.

More than 1 in 5 Americans aged 50 and older now say they’ve used marijuana at least once in the past year, according to the survey conducted by the University of Michigan, while more than 1 in 10 consumed cannabis at least monthly. Researchers said they expect use rates among older adults to continue to increase as more states legalize.

The new findings come after a separate study earlier this year concluded that cannabis-based products may provide multiple therapeutic benefits for older adults, including for health, well-being, sleep and mood.

Authors of that study, published in the journal Drugs and Aging, also observed “sizable reductions in pain severity and pain interference among older aged patients [reporting] chronic pain as their primary condition.”

Researchers said that investigation was meant to address “a general paucity of high quality research” around cannabis and older adults “and a common methodological practice of excluding those aged over 65 years from clinical trials” at a time when older patients are increasingly turning to medical marijuana for relief.

“International evidence that older individuals may be the fastest-growing increase in the use of medical marijuana, coupled with their frequent exclusion from controlled trials, indicates a growing need for real-world evidence to assess the effectiveness and safety of these drugs for older individuals,” the paper said.

Meanwhile, U.S. officials at the National Institutes of Health (NIH) announced this spring that the agency will use $8.4 million to support clinical trials into the safety and efficacy of psychedelic-assisted therapy to treat chronic pain in older adults.

A government notice about the grant program says the research can include “classic” psychedelics—including psilocybin, DMT, LSD and mescaline—as well as similar compounds such as MDMA. Cannabis and ketamine are not considered psychedelics for the purposes of the clinical trials.

A federally funded study last year found that among U.S. adults, cannabis and psychedelic use were both at “historic highs,” while teen marijuana use remained stable.

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Photo courtesy of Chris Wallis // Side Pocket Images.