IN MARIJUANA DEBATE, BOTH SIDES CAN POINT TO THE SCIENCE

Bill Would Make Minnesota the 13th State to Allow Medical Uses Within
Strict Limits.

If marijuana were a new discovery, without cultural and political
baggage, "it would be hailed as a wonder drug," wrote Dr. Lester
Grinspoon last year. The Harvard psychiatrist has advocated for
medical marijuana for decades.

Yet a gap has persisted between what many believe about medical
marijuana's potential and what scientists could prove. Now recent
research has applied the same rigor that would be used on any new
pill to testing marijuana.

The results, so far, give ammunition to both sides of a debate at the
Minnesota Legislature, where a medical marijuana bill has passed the
Senate and a House committee. It would make Minnesota the 13th state
to allow medical uses within strict limits.

Politics aside, what does science conclude at this point about
medical marijuana?

No Argument

Scientists agree on one thing: the active ingredient in marijuana,
THC, has some healing powers. In 1985, the U.S. Food and Drug
Administration (FDA) approved the pill Marinol, a synthetic form of
THC, to relieve nausea and vomiting from chemotherapy. A few years
later, the pill also won FDA approval to stimulate the appetite of
people wasting away from AIDS or cancer.

Pill vs. Plant

The debate, medically speaking, is about smoking a plant or swallowing a pill.

Government scientists agree research shows smoking marijuana gets THC
into the bloodstream faster than a pill.

But the FDA argues that marijuana must go through the same hurdles as
any medicine to be proven safe and effective, and that it's
impossible to ensure the dose and potency of something that grows
wild. The FDA has never approved any medicine to be smoked.

Also, marijuana is listed as a Schedule I controlled substance, the
most restricted class of drugs in federal law. It's a category
reserved for drugs with a high potential for abuse, no accepted
medical uses and no safety data for medical use.

Promising Research

Supporters claim marijuana can help treat hundreds of conditions,
from depression to malaria.

But the strongest scientific evidence points to a shorter list,
according to medical groups. One of the most promising areas is pain relief.

In 1999, the Institute of Medicine (part of the National Academy of
Sciences) conducted the most extensive review of scientific
literature of marijuana and concluded that its chemical compounds
"likely have a natural role in pain modulation, control of movement
and memory."

Until recently, "medical studies, at least meeting modern standards
. have been lacking," said Dr. Igor Grant, director of the Center
for Medicinal Cannabis Research at the University of California, San
Diego, which has spearheaded much of the latest research. "There has
been quite a lot of anecdotal evidence, uncontrolled research, that
there may be benefits."

To win over scientists, the research generally has to show that a
drug works better than a placebo, and that neither scientists nor
subjects knew who was getting the real thing.

Since 2007, a handful of government-approved studies at the
University of California have found that smoking marijuana can help
relieve neuropathic (nerve) pain from injuries or diseases such as
AIDS and cancer. In each case, half the volunteers were given
marijuana and the other half a fake substitute. They found a
measurable difference.

But researchers also turned up some cautionary notes. One study,
released in October, tested three different concentrations of
marijuana, and found only one -- the middle dose -- provided
"moderate pain relief." The lowest dose showed no effect and the
highest dose actually increased pain, the study found. Another study
found pain relief came with a worrisome downside: psychological impairment.

Still, the growing body of research has won over some major medical
groups, such as the Leukemia and Lymphoma Society, and the American
College of Physicians, which represents 125,000 internal medicine
specialists. Both support lowering legal hurdles for medical marijuana.

Mixed Results

Scientists have also tested marijuana's active ingredients on other
conditions, such as glaucoma and multiple sclerosis. Results have
been mixed and scientists say there's no proof that it's better than
existing drugs.

Studies suggest THC can reduce eye pressure associated with glaucoma,
but that the effects are shortlived; and scientists worry that the
side effects, especially on the heart, could pose an even greater
danger to elderly patients.

With multiple sclerosis, studies have found fleeting improvement in
spasticity, or muscle contractions, but that THC worsened patients'
balance and control. The MS Society has called for more study.

The Downside

Like many drugs, marijuana has a long list of possible side effects.
Some are part of the marijuana folklore: It makes people high, slows
reaction time, impairs memory, makes people sleepy. Other effects are
more ominous: It can cause a drop in blood pressure, fast heart beat,
heart palpitations, anxiety, apathy, dizziness and depression.

Like tobacco, it contains toxic chemicals that can endanger pregnant
women and cause cancer, lung damage and pneumonia.

The Future

Scientists are testing vaporizers and skin patches as alternatives to
smoking marijuana.