Medical Marijuana: How The Evidence Stacks Up

[bobandtorey]

http://www.scientificamerican.com/article/medical-marijuana-how-the-evidence-stacks-up/?utm_medium=twitter&utm_source=twitterfeed

 

 

May 1, 2014 |By Roni Jacobson

 

 

New York is on track to become the 21st state to legalize medical marijuana this year, and two states—Colorado and Washington—have decriminalized recreational use as well. Americans now overwhelmingly support fewer restrictions on marijuana, with 86 percent saying doctors should be allowed to prescribe the drug for medical purposes.

Despite its surging popularity, the jury is still out on whether marijuana is truly the panacea its supporters claim it to be. Until recently, the drug's illegal status impeded rigorous study of its effectiveness. Several research groups are now taking advantage of today's looser laws to seek out answers. Here is where we stand for the six most studied conditions.

Cancer

Numerous trials have indicated that medical marijuana increases appetite and reduces chemotherapy-related nausea in the short term. Yet it may not be as effective as other recently developed drugs, so marijuana is not considered a first-line treatment for these symptoms.

Epilepsy

Multiple animal studies have suggested that THC, one of the main psychoactive chemicals in cannabis, may inhibit the brain processes thought to cause seizures. High-quality human studies are lacking, however, leaving many open questions.

Glaucoma

Several studies have found that smoking marijuana lowers pressure inside the eye, relieving glaucoma-related discomfort for about three to four hours. Yet a number of pharmaceutical drugs have been shown to be more effective and longer lasting than medical marijuana.

HIV/AIDS

In one randomized controlled trial, patients given a cannabislike compound were twice as likely to gain weight as patients given a placebo—a boon for people battling the wasting effects of this disease. The treatment's long-term effectiveness remains untested.

Multiple sclerosis (MS)

A large trial published in 2012 found that a cannabis extract significantly decreased muscle stiffness and other MS symptoms. A smaller study found that smoking cannabis worked better than a placebo in reducing both spasticity and pain in treatment-resistant participants. Given the few therapies available for MS, a 2011 review concluded that medical marijuana might be a viable way to manage certain symptoms.

Pain and inflammation

Studies have suggested that marijuana is only slightly better than a placebo in reducing acute inflammation, and it may even increase the perception of pain in some patients. When taken in combination with other medications, however, various cannabis-derived drugs have been shown to be moderately effective for reducing chronic neuropathic pain.

Medical Marijuana's Deep Roots

Edited April 22, 2014 by bobandtorey