Testing of cannabis and its derivatives has also begun on type 1 diabetes, rheumatoid arthritis, stroke, Tourette syndrome, epilepsy, depression, bipolar disorder and schizophrenia. Pertwee is particularly optimistic that cannabis will help people with post-traumatic stress disorder. Experiments in rats show that THC “speeds up the rate at which the animals forget unpleasant experiences,” he says. And a recent study in people with PTSD showed that THC capsules improved sleep and stopped nightmares.
Despite these heady beginnings, medical cannabis still faces an uphill climb. Although some states have sanctioned its use, no smoked substance has ever been formally approved as a medicine by U.S. regulatory agencies. Smoking cannabis can lead to chronic coughing and bronchitis, and smoking renders a drug off-limits for children, Mechoulam notes.
THC pills don’t have these downsides, but the drugs have received only lukewarm acceptance. Despite smoking’s drawbacks, “it is seen as better because you can regulate the amount of THC you’re getting by not puffing as much,” says pharmacologist Daniele Piomelli of the University of California, Irvine. Capsules can cause dizziness and make it hard to focus. “Patients suffering from neuropathic pain or depression don’t want to be stoned – they want relief,” he says.
Controlled, randomized trials that seek to clarify whether smoked cannabis delivers on its medical promise – with acceptable side effects – have been hard to come by. But scientists in California have recently concluded several studies in which patients with severe pain received actual cannabis cigarettes or cannabis cigarettes with the cannabinoids removed.
In one trial, researchers randomly assigned 27 HIV patients to get the real thing and 28 to get fake joints. All the patients had neuropathic pain, in which neurons can overreact to even mild stimuli. About half of the people getting real cannabis experienced a pain reduction of 30 percent or greater, a standard benchmark in pain measurement. Only one-quarter of volunteers getting the placebo reported such a reduction.
“That’s about as good [a reduction] as other drugs provide,” says Igor Grant, a neuropsychiatrist at the University of California, San Diego, who is among the scientists overseeing the trials.
While such studies provide evidence that smoked marijuana has medical benefits, future trials are more likely to explore the benefits of cannabis derivatives that don’t carry the baggage that smoking does.
Ultimately, the fate of medical cannabis and its derivatives will rest on the same make-or-break requirements that every experimental medicine faces – whether it cures a disease or alleviates its symptoms, and whether it’s tolerable.
“We have to be careful that marijuana isn’t seen as a panacea that will help everybody,” Grant says. “It probably has a niche…. We can’t ignore the fact that cannabis is a substance of abuse in some people.”
Not just a high. By- Seppa, Nathan, Science News, 00368423, 6_19_2010, Vol. 177, Issue 13