The Progress and Pitfalls of Medical Marijuana

By Katharine Quarmby | August 18, 2015 12:37 pm

medical marijuana

“Cannabis is like a medicine cabinet,” says Roger Pertwee, who was instrumental in some of the early cannabis trials for multiple sclerosis. “It has a lot of compounds in it that are novel and unique to cannabis. We have discovered 104 so far, but there are others. There are many potential uses that we have to investigate.”

Pertwee is Professor of Neuropharmacology at the University of Aberdeen and also GW’s Director of Pharmacology (some of his research at the university is funded by the company). His work, alongside that of other researchers including Raphael Mechoulam and Vincenzo Di Marzo, is instrumental in our understanding of the endocannabinoid system, a network of lipids and receptors involved in a wide array of bodily processes, including appetite, memory, pain and mood.

We have two types of cannabinoid receptor: CB1, which is mostly found in the brain and spinal cord, and CB2, which is found mainly on cells in the immune system. These receptors are activated by cannabinoids made by the body (endocannabinoids) as well as synthetic cannabinoids and those present in plants.

Where should medical research focus its efforts exploring medical cannabis? Many prominent researchers, including Pertwee, believe that the individual components of cannabis are more effective than using the whole plant. Focusing on components would also obviate the need for a patient to smoke.

Areas of interest to researchers across the world include the possible therapeutic use of THC (the main psychoactive component of cannabis), CBD and other cannabinoids to treat autoimmune diseases, diabetes, cancer, inflammation, seizures and even psychiatric disorders, such as schizophrenia.

Cannabis for Cancer

At the medical school at St George’s, University of London, Dr Wai Liu and his team have shown that cannabinoids target the signalling pathways that are mutated in cancer cells, which, effectively, tell cells to keep growing. THC and CBD can turn these signals off, which may reverse the process of cancer in the cells. The compounds also enhance the action of radiotherapy.

But Liu, too, is skeptical of a whole-plant approach. “We have an amazing chance to use a drug derived from the cannabis plant which seems to be anti-cancerous. Let’s research it, and combine it with other cancer drugs. Let’s not waste time.

“If you truly believe that anti-cancer is the argument, don’t talk about cannabis any more, in the same way that we don’t talk about white willow any more because we have aspirin… We don’t need to be hijacked by other motives, like whether or not to legalize cannabis.”

The apparently encouraging results of this kind of work have led some patients to buy cannabis oil online, which is illegal in the UK. Liu is concerned that patients could be self-medicating with oil that could be contaminated. Another problem, he says, is that other chemicals within cannabis (minor cannabinoids) could actually counteract the beneficial effects of THC and CBD. He is now asking the many medical cannabis users who email him if he can collect their data, as a potential precursor to a full clinical trial. “We need to understand the drugs being sold on the internet,” he says.

These minor cannabinoids could be helpful too. Pertwee explains: “We were looking at the history of tincture of cannabis in the past. We found it contains tetrahydrocannabivarin (THCV)”. The researchers have since found that THCV blocks the CB1 receptor but partially activates the CB2 receptor. “This might be good for treating stroke and it might be good for drug dependence,” he says. Other potential uses are being investigated, including for Parkinson’s and schizophrenia.

Evidence for Medical Marijuana

But it’s still early days. While some cannabis enthusiasts see it as a panacea – especially appealing when so many conditions aren’t well treated by other drugs – as yet, evidence across the board just isn’t there.

In summer 2015, a review of the efficacy of medical cannabis for a number of conditions was published. Examining 28 databases, the authors found moderate evidence that medical cannabis may help with spasticity in multiple sclerosis and with neuropathic and chronic pain. But evidence for other conditions was weaker.

A nurse carries medical cannabis in Rehovot, Israel. Credit: ChameleonsEye / Shutterstock

A nurse carries medical cannabis in Rehovot, Israel. Credit: ChameleonsEye / Shutterstock

One major charity, Cancer Research UK, has faced a particularly prominent backlash after voicing caution about cannabis. Its Science Communications Manager, Dr Kat Arney, showed me her bulging folder of research papers about cannabis, embellished with a sticker of Bob Marley. “Cannabinoids are really interesting molecules with potential for human health,” she says. “I read the literature regularly. Nothing tells me that cannabis is a cure for cancer.”

This cautious stance has led to the charity getting flamed on social media. Arney wants case studies to be gathered, saying that the way cannabis in its whole-plant form is discussed by the online community, uncritically, as a cure-all is unhelpful. “At the moment it sounds like – for want of a better word – snake oil, and that’s how it is marketed.”

Legalization Patchwork

Canada, Uruguay, Israel and Jamaica are among the countries that have ruled cannabis legal for medical use. Alongside these sit 23 American states and the District of Columbia, five of which, at the time of writing, have gone as far as legalizing recreational use too.

But what do we mean by medical use? Steve Rolles, from the international think-tank Transform, which campaigns for the legal regulation of drugs globally, sets out some of the options: “Do we want a standardized herbal product like Bedrocan [from specially grown plants], or a tincture like Sativex, or a single-content pharmaceutical product… or a combination of products?

“Would we allow people to ‘grow their own’, as some jurisdictions do, or be provided by ‘compassion clubs’? Who would regulate this activity?”

The stated purpose of most of the American state laws is based on the Californian law: “to ensure that seriously ill Californians have the right to obtain and use marijuana for medical purposes where that medical use is deemed appropriate.” But there is conflict with federal law, under which cannabis is still illegal, and models vary widely across state lines. Alice O’Leary-Randall, one of the earliest American pioneers in the medical cannabis field, says this variation has scattered the movement and dubs it “medical cannabis by zip code.”

Most of these states require the patient to have some form of license to acquire medical cannabis but not all require state residency. Although almost all states have a list of conditions that qualify for medical cannabis, these differ, with some states permitting it for chronic conditions and others only for specified illnesses such as cancer.

Data collected in some states suggests that many medical users receive cannabis for chronic or severe pain, a catch-all, rather than for the conditions on which the first activists campaigned: glaucoma, AIDS, cancer and multiple sclerosis. Certified users in Arizona, for example, are mostly young and male and use the drug for pain relief.

From Medical to Recreational

This, opponents argue, is evidence that medical cannabis has become a first step on the road to recreational legalization, rather than an end in itself. Kevin Sabet, who advised the Obama administration on drug policy, now works as a consultant with Smart Approaches to Marijuana, an organization that opposes legalization. “In the US we are seeing that medical cannabis is being misused to legitimize recreational use,” he says.

“We know that the political movement on medical marijuana is tied to legalization… they have rebranded cannabis, from being about 30-year-old stoners to medical use.” Successfully, too: a 2013 Fox News poll found that 85 percent of Americans – and 80 percent of self-identified Republicans – approve of the medical use of cannabis if prescribed by a medical doctor. But you don’t even need a doctor in some states, as homeopaths and naturopaths can issue licenses.

The amount of cannabis allowed varies. Some states allow patients to grow their own. Others have restrictive medical cannabis agreements, allowing only high-CBD strains (for particular conditions such as epilepsy) – so restrictive, in fact, that patients argue that they are unworkable. The Drug Enforcement Administration has also raided cannabis dispensaries countrywide, saying that they are not just serving medical users.

“There are serious impediments to medical cannabis use within our healthcare system,” O’Leary-Randall says. “There is no consistent education of our healthcare professionals around using medical cannabis, or the endocannabinoid system.” She sits on the board of the American Cannabis Nurses’ Association, which was set up formally in 2012 to give nurses advice on how to assist patients and dispense safely, without violating federal law or their license.

Pharmacists, too, walk a tightrope. Nearly 20 years after the legalization of medical cannabis, the American Society of Health-System Pharmacists (an official body for the profession) encourages research into, but not distribution of, medical cannabis, so qualified pharmacists have historically been unwilling to get involved. Recent discussions by the body, however, suggest a softening of attitude towards medical cannabis. A new body, the National Association of Cannabis Pharmacy, was launched last year.

O’Leary-Randall wants more qualified pharmacists to be involved in dispensing cannabis, though she acknowledges the difficulties: “Cannabis is so unique… It’s rather daunting for elderly people to go into a dispensary and look at names like Purple Haze and Skunk Weed and pick out what is their medicine. I would love to see pharmacists more active in this so we can standardize this and get people more comfortable.”


 This story first appeared on Mosaic. It has been excerpted here.

Top image by Atomazul/ Shutterstock

CATEGORIZED UNDER: Health & Medicine, Top Posts
  • Uncle Al

    The FDA is explicit. Having your GI tract ulcerate from your lips to your nether sphincter is an acceptable side effect. Going deaf or blind can be rationalized. Screams in burn wards are salutary. Getting a buzz is a Schedule I drug or banned outright. “Non tamen solam intendit interiorem, immo interior nulla est, nisi foris operetur varias carnis mortificationes.” Even pleasure by proxy, URB597, is a War on Drugs.

    J Med Chem. 47(21) 4998 (2004)
    Chem Biol. 12(11) 1179 (2005)

    Science must never wear granny panties.

    • Thuxton

      It’s amazing they censor an article about scientific ethics. But the quote deserves searching.

  • rusty

    Funny that some studies are made to fail! Like under doses so certain patients don’t get better! There is a lot of politics in the world of medicine, there is value to people blogging when they treat them self’s with cannabis oil, even when the person is terminal Ill and recover it gets dismissed as hearsay.

    • Vance

      ANYTHING can be proven with statistics if you find the studies to support the particular point you want to emphasize. “There’s lies, damn lies and then there are statistics!”

      • OWilson

        I remember a headline where the rate of HIV was “actually rising faster among high schoolers, than gays”.

        Rates were up 70% among high schoolers and 0nly 20% among gays.

        Of course, the figures behind the statistics were 10 to 17 versus 30,000 to 36,000.

        It pays to be skeptical these days.

  • OWilson

    Since the days of Al Capone, politicians have salivated at the thought of controlling and taxing drugs, gambling, number rackets, alcohol, tobacco, protection racket (aka mandatory universal health care) and prostitution.

    Ironically the mob’s take was less than government’s, and the protection more dependable! :)

    You’ve come a long way, baby!

  • token420

    Recreational use is perfectly legit making this an overall moot situation. Cannabis doesn’t need humans to become “medical” because it already is. The medical and recreational value are built right into the plant, making both medical and recreational use completely viable.

  • ivian

    Sadly “they” don’t really want cancer cured. Just watch Burzynski Documentary, it explains all about a DR. who was curing cancer and what they did to him! For some strange reason, they really would rather you take synthesized prescription meds or Chemo which basically almost kills you before and IF it kills the cancer, than a natural substance (Cannabis) that has more benefits than side effects for a multitude of ailments. Check out why for yourself.

    • Dr. Jeff Kapp


  • Rhonda Weigandt

    Legalize marijuana and prostitution and make them healthier.It makes a lot more sense and its a win win situation. Why be stupid when we don’t have to be.Marajuana is a natural substance. The users could just buy it for their needs and prostitution as we all know will never stop so legalize them both and make them much healthier for everybody.

    • gsmullennix

      Neither should be legalized…that brings in the tax man wanting his share of the loot. They should be made …nothing. The market will make the products better, the prices lower meaning the drug thugs don’t have an artificially high price and sub standard dope to enjoy artificially high margins. Get the cops and government out. Now, on the other hand, if something is going to be come an anti-cancer agent, that should be controlled, data generated, tests reviewed to find out what actually works and what doesn’t. My brother was just on liquid cannabinoids…he went well past the high point. When he came down, the supplier in California, a legal business suggested he reduce the dose.

  • Greig Starton

    If you need good mmj strains and other meds contact 6013404352 or email

    .com and you will get respond asap..

  • Greig Starton

    If you need good mmj strains and other meds contact 6013404352 or email

    .com and you will get respond

  • leronjames

    anyone looking for medical marijuana conection or pain killer meds? text or email: (231) 224-6072

  • Sarah Reid

    Hi Rick, Thanks for your Cannabis Oil as a good news sprang forth while using your cannabis oil medication to treat my Sister’s cancer,

    I have been using some of your cannabis oil in treating my sister rare form of left hand side breast cancer with a lot of improvement since 3 weeks and the cannabis Oil is working in a miraculous way beyond our expectations, We bought the cannabis oil from contact:
    with a THC/CBD potency of 91% and 52% respectively. The medication is working with super proof . She is always Euphoric with THC potency and the medication is working miraculously. Rick, Is the condition of feeling high normal? She is a Mother of 3 kids.


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