“It’s not like you’re out smoking pot for enjoyment or to get high,” says the former social worker, who won’t take the drug during the day because she doesn’t want to feel disoriented. “It’s a medicine.”
For many patients like
As the legal landscape for patients clears somewhat, the medical one remains confusing, largely because of limited scientific studies. A recent American Medical Association review found fewer than 20 randomized, controlled clinical trials of smoked marijuana for all possible uses. These involved around 300 people in all—well short of the evidence typically required for a pharmaceutical to be marketed in the U.S.
Doctors say the studies that have been done suggest marijuana can benefit patients in the areas of managing neuropathic pain, which is caused by certain types of nerve injury, and in bolstering appetite and treating nausea, for instance in cancer patients undergoing chemotherapy. “The evidence is mounting” for those uses, says
But in a range of other conditions for which marijuana has been considered, such as epilepsy and immune diseases like lupus, there’s scant and inconclusive research to show the drug’s effectiveness. Marijuana also has been tied to side effects including a racing heart and short-term memory loss and, in at least a few cases, anxiety and psychotic experiences such as hallucinations. The Food and Drug Administration doesn’t regulate marijuana, so the quality and potency of the product available in medical-marijuana dispensaries can vary.
Though states have been legalizing medical use of marijuana since 1996, when California passed a ballot initiative, the idea remains controversial. Opponents say such laws can open a door to wider cultivation and use of the drug by people without serious medical conditions. That concern is heightened, they say, when broadly written statutes, such as California’s, allow wide leeway for doctors to decide when to write marijuana recommendations.
But advocates of medical-marijuana laws say certain seriously ill patients can benefit from the drug and should be able to access it with a doctor’s permission. They argue that some patients may get better results from marijuana than from available prescription drugs.
The relatively limited research supporting medical marijuana poses practical challenges for doctors and patients who want to consider it as a therapeutic option. It’s often unclear when, or whether, it might work better than traditional drugs for particular people. Unlike prescription drugs it comes with no established dosing regimen.
“I don’t know what to recommend to patients about what to use, how much to use, where to get it,” says Scott Fishman, chief of pain medicine at the University of California, Davis medical school, who says he rarely writes marijuana recommendations, typically only at a patient’s request.
Researchers say it’s difficult to get funding and federal approval for marijuana research. In November, the AMA urged the federal government to review marijuana’s position in the most-restricted category of drugs, so it could be studied more easily.
States’ rules on growing and dispensing medical marijuana vary. Some states license specialized dispensaries. These can range from small storefronts to bigger operations that feel more like pharmacies. Typically, they have security procedures to limit walk-in visitors.
At least a few dispensaries say they inspect their suppliers and use labs to check the potency of their product, though states don’t generally require such measures. “It’s difficult to understand how we can call it medicine if we don’t know what’s in it,” says
Some of the strongest research results support the idea of using marijuana to relieve neuropathic pain. For example, a trial of 50 AIDS patients published in the journal Neurology in 2007 found that 52% of those who smoked marijuana reported a 30% or greater reduction in pain. Just 24% of those who got placebo cigarettes reported the same lessening of pain.
Marijuana has also been shown to affect nausea and appetite. The AMA review said three controlled studies with 43 total participants showed a “modest” anti-nausea effect of smoked marijuana in cancer patients undergoing chemotherapy. Studies of HIV-positive patients have suggested that smoked marijuana can improve appetite and trigger weight gain.
Side effects can be a problem for some people.
Other marijuana users may experience the well-known reduction in ability to concentrate. At least a few users suffer troubling short-term psychiatric side effects, which can include anxiety and panic. More controversially, an analysis published in the journal Lancet in 2007 tied marijuana use to a higher rate of psychotic conditions such as schizophrenia. But the analysis noted that such a link doesn’t necessarily show marijuana is a cause of the conditions.
Long-term marijuana use can lead to physical dependence, though it is not as addictive as nicotine or alcohol, says
Some studies and reviews examining the possible medical uses, and side effects, of marijuana are being conducted by.
* Center for Medicinal Cannabis Research, University of California
* American College of Physicians
* Institute of Medicine
To read more on Marijuana and its effectiveness, the following periodicals have spent time reviewing certain aspects of medical marijuana.
To treat pain:
* Journal of Pain
To treat nausea:
* Annals of Internal Medicine
* Pharmacology Biochemistry and Behavior
To restore appetite:
* Journal of Acquired Immune Deficiency Syndrome
To treat spasticity:
Overviews of Potential Side Effects:
* Canadian Medical Association Journal
* Clinical Toxicology
* Neuropsychology Review
* Current Psychiatry Reports
* Current Opinion in Psychiatry
Effects on Lungs
* Cancer Epidemiology, Biomarkers & Prevention