Experts discuss science of med. Marijuana
With San Diego set to grant 36 new permits for medical marijuana dispensaries this year, the drug is about to become more legitimate than ever in the city.
Does that mean cannabis is good medicine?
Only solid science can prove what human ailments the green, leafy plant can truly soothe, but science has never been in the driver’s seat as far as marijuana is concerned.
Californians approved the Compassionate Use Act in 1996, giving doctors broad leeway to prescribe the drug if they determine “that a person’s health would benefit from the use of marijuana in the treatment of cancer, anorexia, AIDS, chronic pain, spasticity, glaucoma, arthritis, migraine or any other illness for which marijuana provides relief.”
While much more is known today about the medical effectiveness of the species cannabis sativa than in 1996, scientists maintain that they can’t prove efficacy for many conditions that marijuana is routinely used to treat. It’s often difficult to distinguish what’s simply promising from what has peer-reviewed scientific legitimacy, researchers said.
Dr. Igor Grant— Bill Wechter“There is a complexity here. There isn’t always a right answer,” said Dr. Igor Grant, director of the Center for Medicinal Cannabis Research and chairman of the psychiatry department at UC San Diego.
Meanwhile, public opinion on marijuana has undergone a dramatic shift nationwide.
In 1996, a Gallup poll showed that only 25 percent of the U.S. population believed marijuana should be legalized. Last year, with Washington state and Colorado approving the drug for recreational use and 21 states allowing at least some sort of marijuana use, Gallup reported that 58 percent of Americans said yes to the following question: “Do you think the use of marijuana should be made legal, or not?”
In this environment, Dr. Robert Blake is left to apply his own philosophy and understanding to the question of who gets a prescription for medical marijuana and who doesn’t.
Blake, a former emergency physician who started doing medical marijuana assessments in 2009, said he writes the bulk of his prescriptions for pain management.
“Most commonly, the person has pain somewhere. It can be physical or emotional,” Blake said.
In the end, he said, cannabis is a good alternative if the patient would otherwise be prescribed narcotics such as Vicodin.
“My experience is that cannabis very effectively reduces the amounts of narcotics that patients are on,” Blake said.
Another local authority on the issue of marijuana and pain management is Grant at UC San Diego. The goal of his Medicinal Cannabis Research center, which was created by the California Marijuana Research Act of 1999, has been to delve into this question: What are cannabis’ true medical effects?
Over the years, the center has published some of the most widely cited studies on the effects of marijuana on pain. These studies use the most rigorous scientific controls possible, randomly giving some participants placebos and others marijuana to gauge outcomes.
Most of the clinical trials have looked at chronic nerve pain, the kind usually linked to nerve damage associated with HIV, certain cancer treatments and spinal injuries.
“Neuropathic pain is often caused by nerve damage, and it can produce a burning hypersensitivity that is extremely uncomfortable,” Grant said.
Chronic nerve pain, he added, does not always respond to traditional pain medications. Though the center’s studies on this type of pain were small, with 50 or fewer participants, Grant said the results suggest pretty strongly that marijuana can be an effective alternative.
“I’m pretty confident in saying that cannabis is useful in managing neuropathic pain,” he said.
Medical experts also seem to agree that marijuana helps alleviate nausea.
“With neuropathic pain, I would say that it has an effect, but that effect, and what causes it, is not as clear as it is with nausea,” said Dr. Kari Franson, associate dean of professional education at the University of Colorado’s Skaggs School of Pharmacy.
In addition, researchers said there is plenty of evidence that the drug is an effective appetite stimulant for patients with cancer and HIV. Franson noted, though, that other medications can do a good job of stimulating appetite.
“The reality is, very few people use marijuana for that,” she said.
Studies also support the use of marijuana to control spasticity in multiple sclerosis patients in cases where they may not respond well to other drugs, Grant said.
“Sure, there are other treatments available, but they don’t work with everybody, and not everybody can take enough of those other medications to have an effect,” he said. “Here, cannabis seems to have another (beneficial) role.”
Interest in CBD
The latest marijuana trend focuses on cannabidiol, which most people simply call “CBD,” one of 66 chemical compounds unique to cannabis sativa.
Unlike its cousin tetrahydrocannabinol — usually called THC — cannabidiol does not produce a euphoric high. And some studies indicate that cannabidiol may be useful in controlling seizures, including those that occur frequently in epilepsy patients.
Recently, parents with young children who suffer rare forms of epilepsy that cause debilitating seizures have received significant media attention because they give those kids marijuana extracts with high levels of cannabidiol.
The publicity has made the phone ring a lot at PharmLabs in Ocean Beach, which tests marijuana flowers, leaves and other bits for their levels of THC, CBD and other compounds. PharmLabs’ clients include sellers of medical marijuana.
“We’re constantly getting calls. It’s just ‘CBD, CBD, do you guys test for CBD?’” said PharmLabs co-owner Greg Magdoff.
Grant said from the viewpoint of scientific research, there is less evidence for marijuana’s effectiveness against epileptic seizures.
“With epilepsy, there really have not been the level of clinical trials to make me comfortable to say that, ‘Yes, this works,’” he said.
But advocates of medical marijuana have touted in recent years that seizures can be greatly reduced — or even eliminated, according to some anecdotal reports — by dosing with CBD-rich variants of pot.
While he has seen those reports, Grant said the anecdotes simply have not been proven with the full discipline of controlled scientific experiments. “If it helps your child, that’s great, but that doesn’t mean it will help all children,” he said.
Still, Grant said he does not fault parents for trying cannabis extracts on children who get little to no relief from FDA-approved medications for rare forms of epilepsy or other seizure-causing illnesses.
Beyond seizures, Magdoff said people are using marijuana to treat tremors and other symptoms of Parkinson’s disease.
Grant said there is anecdotal evidence that marijuana can help with Parkinson’s, but nothing yet from clinical trials.
Experts discuss Marijuana is also promoted as being able to slow the spread of cancer, treat inflammation, fight fungal infections, aid with sleep and curtail bacterial growth.
None of these uses has been substantiated on a scientific basis, Grant said.
Even ailments for which there is some scientific proof that marijuana is good medicine still need further research, said experts such as Grant and Franson at the University of Colorado. They said the testing should include more participants and be conducted over longer periods of time.
“Much larger clinical trials with much more varied groups of patients are needed,” Grant said. “It’s possible that what is safe and effective in a 30-year-old, for example, may not be in a 70-year-old.”
The aim of offering more comprehensive — and thus more expensive — research is thwarted by the fact that marijuana remains classified as an illegal drug by the federal government.
The federal drug schedule lists cannabis among “Schedule I” drugs such as heroin, LSD, ecstasy and peyote. These substances are defined “as drugs with no currently accepted medical use and a high potential for abuse.”
By comparison, cocaine and methamphetamine are “Schedule II” drugs — considered to have “less abusive potential” than marijuana.
So while San Diego County is home to numerous unlicensed marijuana dispensaries and delivery services, and while state law has allowed residents with valid prescriptions to grow their own pot plants since 1996, scientific researchers must obtain the drug from a single licensed farm at the University of Mississippi.
Grant said getting federal approval to obtain marijuana from that farm takes six to 18 months.
A state bill approved in 1999 provided $8.7 million to fund his center’s studies, but that money has been depleted. Grant said that only one more study — examining marijuana’s effects on people with chronic diabetes — remains to be published.
Today, it is Colorado that seems most able to continue research with new clinical trials funded by the excise taxes collected on recreational marijuana sales that started in the state on Jan. 1.
Even then, the federal legality issues make it difficult for Colorado to conduct its own research and stay in good graces with drug czars in Washington, D.C., said Franson at the University of Colorado. She also serves on the governor’s task force that was created to determine how to spend marijuana tax money.
“We are trying to find a way to work with local authorities to move forward, but because we receive federal money, we have to be cautious,” she said.
She also noted that one particularly practical consideration for a state that just legalized marijuana for recreational use is the fact that no one really knows at what point a person consuming marijuana becomes impaired.
Franson, who did research on marijuana in Amsterdam, where drug policies are much more lenient, said it is clear that marijuana impairs coordination, concentration and short-term memory, but that it is unclear how those impairments scale as a person smokes joint after joint.
“The whole idea is, how do we enhance the safety of the people who are using it?” she said.