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Until its prohibition in 1937, extract of Cannabis sativa (marijuana) was one of the top three most prescribed medicines in the US. When it became illegal, its use as a medicine became restricted. Despite these regulations research on the medical use of marijuana continued.

In recent years, when some states decided to legalize smoked marijuana for certain patients, medical marijuana became a subject of contentious debate. Should patients be allowed to grow their own plants? Might medical use inevitably lead to recreational use?

Listen to our complete medical marijuana podcast.

Immune System (thymus)

CB2 Cannabinoid Receptor

T-cells

Brain

CB1 Cannabinoid Receptor

There are two types of cannabinoid receptors in the body. CB1 receptors are expressed on the surface of neurons, and CB2 receptors are expressed on cells of the immune system.

The active compounds in marijuana are similar to a class of molecules in our bodies called endocannabinoids. Both bind to receptors in the brain and throughout the body called cannabinoid receptors. This system influences our immune system, protects nerve cells from premature death, and influences mood, memory, appetite, sleep and movement.

Dr. Robert Melamede

"Endocannabinoids regulate every one of the systems in our bodies."

Marijuana contains approximately 66 active compounds with different properties, collectively called cannabinoids. Scientists are currently studying cannabinoids in an effort to understand their individual and combined effects, and their potential benefits.

Research and anecdotal evidence suggest that there are conditions for which medical marijuana may be the most effective treatment.

"There are different kinds of pain."

Cancer - Relieves nausea during chemotherapy treatment.

AIDS - Increases appetite in patients experiencing severe weight loss.

Neurological disorders (including spinal cord injury and multiple sclerosis) - Reduces pain and spasticity resulting from nerve damage.

Inflammatory pain - Cannabinoids seem to be more effective than opiates in treating long-term, chronic pain (opiates are better for treating short-term acute pain).

Autoimmune diseases (such as arthritis) - Suppresses the immune system resulting in less pain and inflammation.

Dr. Robert Melamede

The active compounds in marijuana are available in several forms, and can be administered in a variety of ways. Each delivery method has its own benefits and disadvantages.

In 1970, Congress classified cannabis and THC (one of the active compounds in cannabis) as Schedule I drugs under the Controlled Substances Act. Schedule I drugs are defined by Congress as having no medicinal value. The one exception to this classification allows for use in FDA-approved research programs.

VT

ME

DC

RI

WA

CO

MT

OR

HI

AK

NV

CA

As of January, 2006, 11 states and the District of Columbia have legalized medical marijuana. Each state has its own regulations to control details such as allowable quantities and registration requirements. However, in June of 2005, the Supreme Court ruled that individuals in all states can still be prosecuted under federal law, under which medical marijuana remains illegal under the Controlled Substances Act.

Smoking marijuana

Delivers all of the plant's active compounds.

Easy to regulate dose (patients smoke until symptoms are eased, but are not intoxicated).

No standardization. Amounts of active ingredients may vary.

Burning marijuana produces toxins which can cause emphysema and lung cancer.

Illegal in most states.

Marinol - Synthetic THC in pill form.

Legal in US.

Delivers some of the benefits of marijuana.

Difficult to control dose.

Contains only one of the plant's active compounds (THC). Patients report fewer of the positive effects associated with marijuana, with more negative side effects.

Vaporizor - Converts the active compounds in marijuana to inhalable form, without releasing toxins.

Delivers all of the plant's active compounds.

Easy to control dose.

No standardization. Amounts of active ingredients may vary.

Illegal in most states.

Sativex - Extract from cloned marijuana plants delivered as a spray.

Contains all of the plant’s active compounds.

Concentrations of active ingredients are standardized.

Relatively easy to regulate dose.

Legal only in Canada and the UK. Clinical trials are under way in the US for treatment of Multiple Sclerosis.

If medical marijuana were legalized in all states, there might be repercussions outside the realm of medicine. Opponents worry that legalizing medical marijuana might lead teens to believe that marijuana is safe for recreational use and increase availability of the drug. On the other hand, some supporters think changing the perception of marijuana from a party drug to a medication might make it less attractive to teens wanting to defy or rebel.

"Studies show that Sativex (marijuana extract) is not as addicting as legal prescription medications such as opiates."

Dr. William Notcutt,
director of Sativex trials

Opponents worry that medical marijuana might lead more teens to use marijuana recreationally.

Some argue that Congress should change marijuana's classification under the Controlled Substances Act. If it were no longer a Schedule I drug, its medicinal benefits could be recognized legally. But opponents fear that legalizing marijuana for medicinal purposes would open the door to its legalization for recreational use.

Legalized medical marijuana also presents law enforcement with challenges. How would federal, state and local governments control and regulate the production, distribution and sale of medical marijuana? Who would define what is recreational versus medical use of the drug, and how would that be enforced?