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Medical Marijuana

Pa. medical marijuana cards and anxiety: What the research says

by Ed Mahon of Spotlight PA |

A stylized illustration of a marijuana leaf
Leise Hook / For Spotlight PA

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Anxiety disorders are the leading reason doctors approve patients for a medical marijuana card in Pennsylvania, even though the evidence that cannabis or its compounds are an effective treatment for them is limited and mixed.

A Spotlight PA analysis found that, in 2021, anxiety disorders were listed as the sole qualifying condition on more than 151,000 medical marijuana certifications — or nearly 40% of the ones created that year.

Anxiety ranked far ahead of chronic pain, post-traumatic stress disorder, and other conditions. Recently released data from the Pennsylvania Department of Health shows anxiety continued to dominate the medical marijuana program in 2022.

If you’re considering using cannabis for anxiety, Spotlight PA collected some research and other resources that could be useful.

National Academies

A comprehensive review by the National Academies of Sciences, Engineering, and Medicine of scientific research looked at the health effects of cannabis and its compounds for a range of conditions.

The strength of the evidence varied from condition to condition.

For instance, the committee of experts who created the consensus report in 2017 said there was conclusive evidence that oral cannabis compounds are effective at treating chemotherapy-induced nausea and vomiting. The committee determined there was substantial evidence that cannabis is an effective treatment for chronic pain in adults.

The evidence in support of cannabis and its compounds as a treatment for anxiety was weaker, the committee found.

The report specifically looked at the potential benefits of the cannabis compound CBD, which does not cause impairment or produce a “high” feeling, according to the CDC.

The authors found there was limited evidence that CBD is effective for improving anxiety symptoms, as assessed by a public speaking test, for people with social anxiety disorders, and the report cited a randomized trial that compared a single dose of CBD to a placebo in 24 participants with generalized social anxiety disorder.

The National Academies report also found potential downsides to cannabis for anxiety, stating that “evidence from observational studies found moderate evidence that daily cannabis use is associated with increased anxiety symptoms.”

The committee also said there were research gaps, including those related to CBD’s effectiveness for short-term relief from anxiety symptoms.

Other states

The Minnesota Department of Health’s Office of Medical Cannabis published a 48-page report in 2021, reviewing the existing research around anxiety and cannabis while also evaluating the potential impact of adding it to the state’s list of qualified conditions.

“Overall, the available published research provides mixed evidence of efficacy,” the report said.

The report described several limitations in the relevant research, saying that most of it has involved healthy people and “a limited number of studies specifically focus on individuals with a diagnosed anxiety disorder.” The ability to compare findings from observational cohort studies is also limited, the office said, because of inconsistent variables.

Cannabis’ status as a Schedule I drug — a category the federal government uses for drugs it considers to have no currently accepted medical use and a high potential for abuse — complicates attempts to research the drug, the office said.

In 2022, the New York State Department of Health AIDS Institute developed guidelines to help clinicians working with medical marijuana patients.

The guidelines didn’t examine whether cannabis is effective at treating anxiety. However, the report did offer advice to clinicians for treating patients who use cannabis.

“Chronic cannabis use is associated with psychiatric symptoms, including anxiety, depression, and psychosis, and has been linked to worsening schizophrenia in individuals with a preexisting genetic vulnerability,” the research team wrote.

They added that it was difficult to establish a direct causal relationship between cannabis use and psychiatric illness. People with anxiety or stress might, for instance, be more likely than the general population to use cannabis.

The report encouraged care providers to monitor patients for new or worsening psychiatric symptoms, and if they identify them, “discontinue medical cannabis certification and consult with a psychiatrist or refer the patient for psychiatric assessment and treatment.”

The studies that Pa.’s former health secretary reviewed

Anxiety disorders were added as a qualifying condition in Pennsylvania under then-Gov. Tom Wolf.

After Rachel Levine, the state’s then-health secretary, approved the addition in 2019, she told fellow members of the state’s Medical Marijuana Advisory Board that she had “carefully reviewed the literature.”

Levine referred to “some of the key articles” she could provide board members but didn’t cite any specific studies during that August 2019 meeting. The department later provided a resource guide to Spotlight PA in response to an open records request for those and other articles Levine reviewed to determine whether to add anxiety as a qualifying condition.

The list included over 20 articles and reports. Their focus varied, and the guide did not clarify how Levine analyzed the information in them. Overall, the articles presented a nuanced take.

In the first item listed in the resource guide, researcher Susan Stoner described the effects of marijuana on anxiety disorders as “complex.”

Stoner made a distinction between what she called the two primary active ingredients of marijuana, THC and CBD, which she said “appear to have differing effects with regard to anxiety.” While CBD is not considered an impairing compound, THC is.

“Pure THC appears to decrease anxiety at lower doses and increase anxiety at higher doses,” wrote Stoner, now a research associate professor at the Addictions, Drug & Alcohol Institute at the University of Washington School of Medicine. “On the other hand, pure CBD appears to decrease anxiety at all doses that have been tested.”

The cannabis plant includes many compounds, and Stoner wrote that it is “largely unknown how the interaction of THC and CBD plays out in practical use of marijuana by medicinal and recreational marijuana users.”

Stoner told Spotlight PA she was surprised to see her 2017 report included in the Wolf administration’s resource guide for anxiety. She described it as a white paper that was not peer-reviewed, although it cited articles that were.

In the report, she wrote that there may be some short-term benefit to using marijuana to cope with anxiety, but the white paper also describes potential downsides to cannabis use and limitations in existing research.

Her report didn’t endorse adding anxiety as a qualifying condition for state medical marijuana programs, and she told Spotlight PA she has concerns about the message that type of addition sends.

“There’s a risk when people see that they think, ‘Oh, well the state of Pennsylvania endorses this. It must be effective,’” Stoner said. “And that would be a fallacy.”

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