Some patients swear by it, but science has yet to catch up with their claims. Even so, 14 state legislatures and the District of Columbia have carved out a big exception to the usual definition of "medicine."
Fourteen states and the District of Columbia have launched a medical experiment that doesn't follow any of the rules of science.
By approving the use of marijuana as a medicine -- with varying kinds of restrictions -- these jurisdictions are bypassing the federal government's elaborate processes for approving medicines.
That's highly unusual. In fact, it's only happened once in recent memory: In the late 1970s, about half the states legalized the use of laetrile, an extract of apricot pits, as a cancer treatment. At least 50,000 cancer patients took it before it was exposed as totally useless.
Nobody argues that marijuana is the new laetrile. For one thing, nobody's claiming it cures any fatal diseases. But it is a departure from the usual rules of evidence for drugs.
Struggling With Chronic Illness
If you want to understand why it's happening, you should spend some time with Ellen Lenox Smith of suburban Rhode Island: a lively, petite, 60-year-old grandmother, former schoolteacher and one-time master swimmer.
When you meet Smith, you don't suspect anything's seriously wrong with her health. But in fact, she has two incurable diseases: One, called sarcoidosis, is ravaging her lungs. The other makes her tendons and ligaments loose and fragile.
"My knee tore, and two weeks later the other knee tore," Smith says. "And the same thing with my shoulder. It was one shoulder and then the other shoulder. So I was tearing like tissue paper, and no one knew why."
After years of misdiagnosis and surgical repairs, Smith learned she has a rare genetic disease of connective tissue called Ehlers-Danlos syndrome.
"My condition causes pain throughout the entire body," Smith says. Most people with Ehlors-Danlos "live on morphine and OxyContin," she says, but she has bad reactions to these and nearly all other painkillers. "I can't tolerate them."
An Unlikely Prescription
Feeling desperate with pain and suffering sleepless nights, Smith consulted pain specialist Dr. Pradeep Chopra. This was about four years ago, just after Rhode Island became the 11th state to legalize medical marijuana. Chopra had never recommended marijuana to a patient, and he never imagined he would.
But in Smith's case, he says, "she had absolutely no other option. So very, very hesitantly, I said, 'Listen, why don't you try medicinal marijuana?' "
Smith says, "I can remember laughing and thinking, 'I wish my parents were alive to hear this conversation!' You spend your life being told to stay away from certain things, and here I have a doctor suggesting it could help me."
Smith appealed to one of her adult sons, who scrounged some pot from a friend. Because of her lung condition, she couldn't smoke it, so she soaked it in oil and stirred the oil into applesauce.
"I tried it that night -- scared to death! I mean, I had no idea what to expect," she says. "The only time I'd ever tried marijuana was once in college, and it was so horrible. So I was really nervous about it.
"But it was so amazing! I took this oil, went to bed, and the next thing I know, it was morning," Smith says. "I had literally slept through the entire night for the first time in months."
Patient: Marijuana Saved My Life
She's used marijuana ever since -- sometimes during the daytime, too -- and says she's never gotten high from it.
"I wake up in the morning, my head is clear, I read the papers, do my Sudoku puzzles, and my mind is fine," she says. "Somehow this drug attacks pain, and I get pain relief but I don't get stoned."
This point is controversial. Some researchers believe patients who use marijuana medically do have psychoactive effects, but they have the effect of shifting patients' attention away from their pain, perhaps in addition to a direct pain-relieving effect. JoAnne Leppanen of the Rhode Island Patient Advocacy Coalition says: "What pain patients tell me is, 'Cannabis does not get rid of my pain. It's still there. But I don't care so much.' So it's affecting their mental attitude."
For Smith, relief is far from total, but she can deal with her pain now, especially since she sleeps well. Smith says marijuana has saved her life.
"My husband says it, too," she says. "I don't think I'd be here. I think I probably would have passed away if I didn't have this drug. There was nothing -- nothing left to help me."
A Slippery Slope?
Smith is exactly the kind of patient legislators have in mind when they allow marijuana to be used as a medicine. But some think legalization is dangerous.
"Approving medical use of marijuana by political referendum is a slippery slope," says Joseph Califano, director of the National Center on Addiction and Substance Abuse at Columbia University. "What's the next substance we'll approve by political referendum?"
Califano was U.S. Secretary of Health, Education and Welfare during the laetrile period.
"We have the best system in the world for clearing drugs in the Food and Drug Administration, and that's the system we should follow," he says.
There was a time when Califano's view was the prevailing opinion, but that may not be the case any more. It seems that many in the medical world who once were dead set against medical marijuana are now not so sure.
The FDA specifically opposes smoking marijuana for medical purposes. But spokeswoman Karen Riley said in an e-mail message that the FDA "is willing to consider proposals by investigators to conduct clinical trials using marijuana."
"We do have a number of open investigational new drug applications that study marijuana," Riley writes. "Some of these study the ability of marijuana to treat disease or medical conditions. Some use marijuana to assess treatments for addiction. Some could study the physiological or pathological effects of marijuana in the body."
Problems With Researching Pot
However, scientists say doing research with marijuana requires the patience of Job, largely because the federal government still classes marijuana as a Schedule I controlled substance with no legitimate medical use. That status requires researchers to get a license from the Drug Enforcement Administration, part of the Justice Department. The DEA relies on the National Institute on Drug Abuse, or NIDA, for advice on research proposals.
"I know one research group who says it took a year to get feedback from NIDA," says Dr. John Halpern of Harvard Medical School and McLean Hospital. "Then when they resubmitted their proposal, they got another set of criticisms."
The director of NIDA, Dr. Nora Volkow, declined to be interviewed about medical marijuana.
Research Has Made Headway
But other people in the field are open-minded about the medical uses of marijuana. Take Dr. Glen Hanson, for example. He's a former acting director of NIDA and still advises the agency. He does drug research at the University of Utah, and he heads the Utah Addiction Center.
Hanson is familiar with the scientific evidence on marijuana. Running through a list of things some people claim marijuana's good for, Hanson says there is legitimate support for many conditions.
Pain, for instance. "Yes, there's some significant evidence that it's useful in some types of pain," Hanson says.
Multiple sclerosis? "That's more controversial," he replies. "There are clearly some individuals with multiple sclerosis who say that it helps them."
Glaucoma: "There is some [evidence], but again, controversial."
Seizures: "Again, some evidence that it may be useful in dealing with some seizures."
The list goes on. Hanson says there's evidence for some other claims, but not for others.
The thing scientists are really excited about, Hanson says, is the discovery that many organs in the human body and brain have receptors for the chemicals in cannabis. That observation was first made in 1988, but over the past 10 years scientists have done a lot of work to figure out how these receptors work.
"This area has exploded," Hanson says. "If you're asking is this a system that can be targeted for therapeutic benefit, I think everybody who knows the scientific pieces would acknowledge that potential."
Long Way To Go
But much of the research is in test tubes and animals, not in real patients with real diseases. Human marijuana research is spotty, studies are small and short, and results are conflicting. So there's a big gap between the testimonials -- like Ellen Smith's -- and the science.
Hanson has no doubt that cannabis research will lead to important new designer drugs for a number of maladies. But he has no idea when.
"We don't have a timeline," he says, "Is it going to be five years, 10 years, 20 years? That doesn't satisfy and meet the needs of people who are suffering today. So for me, I have no problem using what we've got -- and today we have marijuana."
Chopra, Smith's physician, agrees. But he's not without misgivings.
"With medicine, we are used to prescribing a fixed dose with a fixed time interval so we can monitor the side effects or the efficacy of a drug," Chopra says. "With medicinal marijuana, it's the other way around. We have no control over the dose or how often it's taken. And so it's really up to the patients to experiment on their own and figure out how much they need and how often."
At the same time, Chopra believes marijuana should be available to patients with no other good options. It's the patients who are driving this movement, he says.
"The people have spoken," Chopra says. "It's basically the people who have come up and said, 'It does help us, look at us, we're doing well.' They're telling the establishment, 'You're wrong,' and the establishment has listened to them."
At least important parts of the establishment are listening. President Obama has said his administration has no interest in prosecuting doctors and patients who use marijuana -- as long as their state allows it. Copyright 2010 National Public Radio. To see more, visit http://www.npr.org/.