Having worked as a data analyst, Darren Forsythe is a self-professed “data guy.” He has also suffered for years from debilitating pain and muscle spasms caused by multiple sclerosis. He’s been on and off a long roster of prescription drugs that have helped relieve his symptoms only to leave him in a despondent fog.

After a drug interaction sent him to an emergency room, he decided to replace his meds with medical marijuana. It’s legal in Colorado, where he lives. But because it’s still illegal at the federal level, doctors can’t formally prescribe the drug. Nor can they say which varieties might work for which patients, at what amount, or even how it should be used (smoked, eaten, inhaled as vapor, or in a spray or topical cream).

To figure out what might work for him, Forsythe drew on his analytical skills and did an experiment in which he was both lead investigator and sole research subject, testing various marijuana-based products. “We’ve used a spreadsheet to keep track of which strains work against which symptoms,” his wife, Joy, says. The couple discovered that one strain, Orange Kush, works well during acute sclerotic attacks; another, Gumbi, can banish a specific kind of pain. Forsythe now uses multiple marijuana-based products, taking care to rotate them. Otherwise, he says, he’s learned that “tolerance builds and efficacy wanes.” 

Good Drug, Bad Drug

Marijuana has an unusual medicinal history. For almost a century, the plant was a legal elixir thought to work against a range of maladies—until changing social mores and bad publicity helped spur its gradual criminalization.

In 1942 the drug was removed from the U.S. Dispensatory, a federal list of approved medications. Congress classified it as a Schedule I substance in 1970—a category that includes heroin—meaning that it had no medical value and a high potential for abuse. And research on the drug would have to be tightly controlled.

Today, marijuana remains a Schedule I drug, but there are signs of change: Federal agencies are considering reclassifying it so that it can be prescribed.

But at the state level, the plant’s status has already evolved. Laws implementing medical-marijuana programs have been passed in 23 states plus the District of Columbia, and for recreational use in four states and D.C., with initiatives pending in several more.

The impetus for that shift depends on whom you ask. Proponents cite mounting evidence of marijuana’s therapeutic value; critics point to public relations campaigns funded by wealthy marijuana entrepreneurs. The two sides are sharply divided over how to regulate the drug. But on this much everyone agrees: Our complicated relationship with marijuana has entered a new and confusing moment.

The discord between state and federal policies has created a morass for patients and doctors. Medical-marijuana products sold to consumers at dispensaries aren’t approved by the Food and Drug Administration. And without federal guidance or oversight, individual states have struggled to establish the kind of quality-assurance protocols that exist for FDA-approved drugs. Also, research into marijuana’s therapeutic value has been hampered. And doctors have been reluctant to step into the fray.

Those shortcomings have forced consumers like Forsythe to take their chances on a product that can be mislabeled or contaminated with pesticides. And it can come with other serious downsides, including panic attacks, cardiac problems, and accidents related to being under the influence. Marijuana use sent about 376,000 people to emergency rooms in 2009, according to the National Institute on Drug Abuse. It’s also addictive for as many as 9 percent of adults and 16 percent of adolescents who use it frequently. And there’s strong evidence that it can trigger early-onset schizophrenia in frequent users who are genetically predisposed.

A Problematic Plant

Marijuana differs from traditional pharmaceuticals in ways that make it difficult for scientists to study. The plant has more than 400 distinct chemical compounds, including about 70 different cannabinoids (chemicals that help produce the “high”), compared with just one or two active ingredients for most FDA-approved drugs. Not only do those cannabinoids have their own individual effects, but they also interact with each other in an untold number of ways. Different ratios of the same compounds can produce significantly different results. And studies of the individual compounds tell us almost nothing about whole-plant medicine.

But to study the whole plant, scientists have had to clear a bureaucratic thicket far denser than for other prospective medications. Not only must the FDA approve the proposed research plan, but the Drug Enforcement Administration also needs to issue a Schedule I license and the National Institute on Drug Abuse has to agree to supply the actual plant materials.

“Any one of these agencies can stop a research project in its tracks,” says J. Michael Bostwick, a psychiatrist at the Mayo Clinic who has studied the history of marijuana’s use. As a result, he says, high-quality research has been at a near standstill for almost half a century.

That’s not to say that research hasn’t been done. In fact, there are thousands of studies and reviews on marijuana’s medical efficacy. But according to a recent editorial in The Journal of the American Medical Association (JAMA), studies to support its use for state-approved conditions are of mostly poor quality; they fail to meet FDA standards. The authors noted that the few credible studies suggest that marijuana can treat pain syndromes, the pain and muscle spasticity from multiple sclerosis, and the nausea caused by chemotherapy drugs. But almost every state that has legalized medical marijuana has cleared it for a longer list of conditions. For example, five states have approved it for the treatment of post-traumatic stress disorder even though the evidence supporting it is weak or nonexistent.

Medical marijuana. Image of marijuana plant leaves.

Flying Blind

Prescription drugs are regulated by the FDA to ensure that they’re safe, effective, consistently produced, and accurately labeled. There aren’t always such guarantees with medical marijuana. At least four states don’t require testing for potency or for contaminants like metals, pesticides, or microbials. Other states that have legalized it have a wide range of policies.

In a study published in 2015 in JAMA, researchers tested edible cannabis from three major metropolitan areas. They found that most product labels were inaccurate. More than half of the products had significantly less of the cannabinoid tetrahydrocannabinol (THC) than was stated on the label; others had significantly more. It’s an issue that experts say extends to all forms of medical marijuana.

A Maze of Regulations

Because marijuana is still currently classified as a Schedule I drug, a patient can’t get an actual prescription for it. Doctors only certify that a patient suffers from a condition for which the drug is approved. Patients then must register with their state to obtain a marijuana-patient ID card. Then they can buy the drug from a dispensary or, in some states, grow their own.

But the protocol can vary widely from one state to another. For a recent study in the journal Health Affairs, Columbia University researchers evaluated state-run marijuana programs. They looked at basic medical criteria, such as whether physicians were required to complete a full medical exam before certifying prospective patients, or whether the program made use of prescription-drug monitoring systems and 30-day refill limits like those used for other controlled substances. They found that out of 24 programs, only those in nine states and the District of Columbia met enough of the standards to qualify as “medical.”

The lack of standards has made some doctors reluctant to even certify prospective marijuana patients. “My malpractice insurance only covers me for the use of FDA-approved medications and treatments,” Alan Berkenwald, M.D., an internist at Cooley Dickinson Hospital in Northampton, Mass., wrote in a recent editorial for The Daily Hampshire Gazette.

In 2002 the U.S. Court of Appeals ruled that doctors who merely recommended marijuana to their patients were protected by the right to free speech under the First Amendment. The attorney general took the additional step of announcing in 2009 that as long as state laws were followed, the federal government wouldn’t penalize doctors or patients for participating in medical-marijuana programs. But those assurances haven’t relieved the concerns of every doctor.

In 1972 and again in 2002, the National Organization for the Reform of Marijuana Laws unsuccessfully petitioned the federal government to remove marijuana from the list of Schedule I substances. The American Medical Association has suggested that the drug be re-evaluated and possibly reclassified. Although the federal government is considering rescheduling marijuana, it has yet to issue a decision. In the meantime, individual states will continue to chart their own course.

Editor's Note: This article and related materials are made possible by a grant from the State Attorney General Consumer and Prescriber Education Grant Program, which is funded by the multi-state settlement of consumer fraud claims regarding the marketing of the prescription drug Neurontin (gabapentin). 

This article also appeared in the June 2016 issue of Consumer Reports magazine.