By Pat Anson, Editor

The perception of marijuana users as pot heads and lazy stoners may finally be changing to a new one: Patient.

According to a new survey by the Pew Research Center, the medicinal value of marijuana is the #1 reason why a majority of Americans now favor its legalization.

The survey of 1,500 adults found that 53% favor legalization, a dramatic shift from a decade earlier when only 32%  favored legalization.

When asked what was the main reason they support legalization now, 41% cited its medicinal benefits. Another 36% said marijuana was no worse than other drugs such as alcohol and cigarettes.

Nearly half of U.S. states have legalized medical marijuana and four states -- Colorado, Washington, Oregon and Alaska -- and the District of Columbia have passed measures to legalize its recreational use. The federal government still classifies marijuana as a Schedule I controlled substance with no accepted medical use, but in recent years has stepped back enforcement efforts in states where it is legal.

But the stigma long associated with marijuana has discouraged physicians from prescribing it and kept pharmaceutical companies from doing extensive research about its medical benefits.

Only two prescription drugs based on cannabinoids – the active ingredients in marijuana — have been approved by the Food and Drug Administration. Nabilone is a synthetic cannabinoid approved for treating nausea in cancer patients. Marinol is also used to treat nausea, and as an appetite stimulant. Both drugs can still be  prescribed “off label” by physicians to treat other conditions.

Some limited studies have found that marijuana is effective in relieving chronic pain and some of the symptoms of HIV/AIDS, cancer, glaucoma, and multiple sclerosis.

"Scientific data indicate the potential therapeutic value of cannabinoid drugs, primarily THC, for pain relief, control of nausea and vomiting, and appetite stimulation," the Institute of Medicine said in a report.

"Smoked marijuana, however, is a crude THC delivery system that also delivers harmful substances. The psychological effects of cannabinoids, such as anxiety reduction, sedation, and euphoria can influence their potential therapeutic value. Those effects are potentially undesirable for certain patients and situations and beneficial for others." 

Efforts to get a medical marijuana spray approved as a drug to treat cancer pain suffered a setback early this year when GW Pharmaceuticals (NASDAQ: GWPH) reported the results of a clinical trial showing that Sativex worked no better than a placebo in relieving cancer pain.

Sativex is getting a "fast track review" from the FDA to treat cancer pain. It is estimated that 420,000 cancer patients in the U.S. suffer from pain that is not well controlled by opioid pain medications.