7 years in, what PA doctors still want to know about Medical Marijuana
Those kinds of studies don't exist with these products,” says a prescribing doctor, “because it has been illegal to study them for most of the last 100 years.
Seven years after its legalization, the medical marijuana industry in Pennsylvania is booming. According to data from the Pennsylvania Department of Health, there were 425,367 active, certified medical marijuana patients in the state as of March.
But while marijuana products are becoming part of the medical mainstream, doctors say there’s still more they wish they knew.
Medical marijuana (also called medical cannabis) was legalized in Pennsylvania in April 2016, with the state’s first dispensaries opening roughly two years later. Patients who meet criteria for one of the 24 serious medical conditions outlined by the state, including autism, anxiety, opioid dependence, cancer, Crohn’s disease and post-traumatic stress disorder, can get physician approval to buy cannabis products at a dispensary.
There are more than 1,800 approved practitioners in the state who can certify patients for medical marijuana use. One of those is Andrew Adams, a primary care provider at Allegheny Health Network and a certifying physician in the Pennsylvania medical marijuana program since its inception.
Andrews says even small quantities of cannabis have been helpful for many of his patients with common complaints including arthritis, neuropathic pain, anxiety and inflammatory bowel disease.
“We can consistently help people with the use of medical marijuana,” he says.
But marijuana differs from traditional medical treatments in one key way: Doctors have limited high-quality research to guide them.
Medical cannabis is not a “one-size-fits-all” solution, says Michael Lynch, associate professor of emergency medicine and medical director for substance use disorder at UPMC. Specific strains, dosages and even particular chemical compounds in cannabis can affect different medical conditions differently.
Teasing out the specific properties of a drug is normally the job of the pharmaceutical industry; in traditional drug development, a compound may be tested in thousands of patients at different dosages for months or even years.
Individuals who take the drug are compared against those who take a placebo to reduce the chances of psychological factors affecting the results, and doctors are often unaware which patient is in which treatment group to prevent expectations from clouding their judgment.
But research of this kind on medical marijuana is difficult to come by.
“Those kinds of studies don't exist with these products,” says Adams, “because it has been illegal to study them for most of the last 100 years.”
Although cannabis products are legal for medical purposes in 38 states, three territories and the District of Columbia, marijuana’s federally illegal status has made it near impossible to conduct the sort of large-scale research necessary to determine which specific compounds work best for which conditions.
Marijuana is a Schedule I substance under the federal Controlled Substances Act, a designation indicating a high potential for abuse and no currently accepted medical use. Heroin, LSD and ecstasy are also Schedule I drugs.
That strict scheduling means two things for marijuana.
First, there’s little federal funding to conduct the sort of expensive clinical trials that would help doctors learn more about cannabis.
Second, research institutions that do manage to secure funding have to jump through a maze of legal hoops to conduct their research.
And while expensive clinical trials are par for the course in the pharmaceutical business — the average cost of developing a new drug is estimated at $2 billion and $3 billion — marijuana offers little return on investment in an industry motivated by profits.
“Nobody owns a patent on cannabis,” says Lynch.
While doctors have learned to get a sense of what works best for their patients and guided them through the trial-and-error process of finding the right cannabis product, both Adams and Lynch say they wish they knew more about how different strains of marijuana and the chemical compounds within them.
“It seems fairly clear to me that the specific cannabinoid or terpene that treats anxiety is not the same cannabinoid that would treat Crohn's disease,” says Adams.
The lack of knowledge is particularly concerning around the issue of anxiety.
While anxiety is by far the highest-cited reason for medical marijuana certifications in Pennsylvania — more than 60% of medical marijuana certifications made in 2021 were for anxiety — doctors say marijuana’s impact on mental health can be complicated.
“There are strains of marijuana that, in general, would not be effective for anxiety, and, in fact, could make anxiety worse,” says Adams.
What’s more, two of the chemical compounds in marijuana — THC and CBD — can have different effects on anxiety at different doses.
A 2017 report from the University of Washington found that while CBD appears to decrease anxiety at all doses, THC can decrease anxiety at low doses but increase anxiety at high doses.
Lynch calls the lack of clear documentation around cannabis’ medical effects a “vicious cycle.”
“It continues to be Schedule I because there’s not enough data,” he says. “And it’s hard to develop data because it continues to be Schedule I.”
Adams agrees. “As long as the federal prohibition remains in place,” he says, “the major players are not going to jump into this space. They just don't want to deal with the legal issues.
“You're not going to see a Pfizer or a Novartis jump into that. And quite honestly, they're the ones that have the kind of horsepower to sort those things out for us pretty quickly.”
