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SKEPTOID BLOG:

Thinking Clearly About Medical Marijuana

by Stephen Propatier

February 6, 2015

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Donate Medical cannabis (aka medical marijuana) is currently being used as a medical treatment. It has many concerning similarities to many types of alternative medicine. Unlike most alternative medicine good research does show promise as a reliable medical treatment. This is a fascinating dichotomy to me as a medical professional and the use of medical cannabis is an interesting thought exercise for the critical thinker. There is good evidence for some uses and myriad of poorly supported treatment modalities. Advocates both for and against demonstrate a disdain of scientific exploration. As a skeptic I think this is fertile ground for flexing our critical-thinking muscles.

Recently, David Noonan at Scientific American wrote a relatively uncritical essay about medical marijuana, called "How Medical Marijuana's Chemicals May Protect Cells." The title is accurate but the operative word for this research is may, yet that is not how he presents the findings. Like most of the positive puff pieces on this drug it lacks a sound scientific critique of the research. Additionally, he expounds medical marijuana's innumerable purported treatments and benefits. He fails to be critical of the research and instead he substitutes a lot of generalized marijuana promotion—a common failing for both sides of the medical cannabis issue. Both the opponents and the advocates rush to judgment and both sides tend to cling to individual research rather than an overall assessment. The liberal application of isolated research and ideologic rhetoric produces a muddy picture. As a skeptic it is always good to take a critical look at controversial medical topics even if you lack the training and the expertise to analyse all the details. Good critical thinking can help you parse the facts from the rhetoric.

Medical marijuana is not like homeopathy or Reiki; it has reasonable plausibility and reasonable evidence to back up some claims. Like those two useless treatments there are reams of in-vitro, unreplicated, or poorly structured research. There is, in my opinion, a "quick-to-judge factor" that surrounds interpretation of all marijuana research by both the pro and con camps. Overall, the research surrounding cannabis is interesting: some promising and some so obviously biased it should be thrown out. But a tiny fraction of the research conducted on the drug has been well structured and replicated. Marijuana as a medical treatment is interesting, complicated, and promising. Let's take a close look and apply our critical thinking skills.

Medical marijuana and the course it has taken on its way to being a medical treatment is to say the least, unusual. Its complicated history, as both an illegal recreational drug and multi-billion dollar criminal enterprise, has tarnished its name. Historically this has thrown up barriers for experimentation and research. Compounding the problems with making this a medical treatment is its advocates' disdain for the current medical system. Many in the pro-medical-marijuana group have a strong leaning towards anti-medical/anti-scientific thinking. And in my opinion this is partly due to medical establishment eschewing them and partly due to purposeful blindness about the drug's shortcomings.

Medical marijuana originated from folk remedies and anecdotes shared among recreational users. After a lot of outcry the medical community finally added its voice to push experimentation and research forward. Proposed applications for this drug seem to have far surpassed available research. That's always problematic for a medical treatment. Although it's true that the illegal recreational use saved a possibly effective drug from the wastebasket, it is also true that the same recreational use has been an impediment for adopting and researching it as a drug.

Historically there was little advocacy in the medical community due to marijuana's negative social connotations. There has long been almost unwavering political and moral opposition to the drug. Those opponents have likewise refused to consider evidence scientifically. They usually oppose the drug due to a social concerns: wide acceptance of an intoxicant, concerns about gateway drug use, or vaguely supported concerns about the consequences of regular use. There are many examples of socially accepted drugs both in medical use (opiates) and recreational use (alcohol) that have identical histories and similar shortcomings. The social and safety issues surrounding this drug aren't significantly different from those drugs.

Both advocates and opponents seem to want to champion research that supports their position and dismiss research that doesn't. That should be a big red flag: the safety and efficacy of a drug needs to be based on science rather than cultural bias, research rather than supposition.

Medical evaluation to quantify and extract usable elements from cannabis have been blunted by both sides. Proponents often advocate that only the whole plant is beneficial, typically describing it as the so-called entourage effect. They claim that isolated compounds are insufficient because there are supposedly undetectable elements to marijuana that cannot be quantified or measured, that the active ingredients are too synergistic, numerous, or complex to separate and use. However, there are no well-controlled studies for inhaled cannabis. This organism varies species to species and plant to plant. There is no way that you are getting a consistent product from the straight plant—no way that something that is so content-arbitrary then requires a very specific combination to achieve efficacy. You can't have it both ways and expect predictable, safe results. Consequently, the weak whole-plant argument has become the fall back special pleading whenever the plant or its products individually fails in research.

Opponents reject plant use because of the perception that it is a foot in the door for an intoxicant. Opponents also point out that its products don't provide any new treatment options, and we already have effective drugs that do what this drug does. Although this is a reasonable criticism, if you look at this objectively you will see a paucity of direct evidence in comparative studies. The answer is that we don't really know if it is superior, equivalent, or worse than existing drugs. Individual elements have been dosed and researched, such as nabiximols in Canada and the United Kingdom. Like most good evidence supporting medical cannabis, the nabiximols study shows modest results on relatively subjective complaints like pain. Combination drugs are being explored, but there are no solid findings yet. To many critical thinkers this is not a strong showing. For any other drug this would be evidence far too weak to promote one treatment over another already proven to be effective.

Medical marijuana offers other pseudoscientific red flags. One typical of many other useless alternative/complementary medicine paradigms is the medical panacea fallacy. Like many other sham treatments, you can name a medical problem and someone will claim that cannabis supposedly treats it. The list of proposed benefits for medical marijuana is ridiculously long, and includes reported maladies such uses as:







all cancers
glaucoma
Asperger's syndrome
Crohn's disease
multiple sclerosis
post traumatic stress disorder
trigeminal neuralgia
epilepsy
nightmares
reflex sympathetic dystrophy
bipolar disorder
anxiety
headaches
depression
meningitis
attention deficit disorder
vomiting
lupus
Hashimoto's encephalopathy
Post-polio paralysis
heroin addiction
Tourette's syndrome
spastic paraplegia
irritable bowel syndrome
hiccups
etc.

Yes: that list includes both cancer and hiccups. When it comes to medical treatments there are no cure-alls. Frankly, it is impossible for any drug to be a panacea. It is totally implausible that medical marijuana could treat even a tiny fraction of these diseases. Good critical thinking has repeatedly shown us that if something is a treatment for everything, then it probably treats nothing. I think medical marijuana is an exception to that rule insofar as it definitely has potential medical applications. But there is no way that it treats that many different medical problems. Anecdotally it may work, possibly as a dissociative, which is just hiding problems not treating them.

Critically the most concerning thing about medical cannabis is the push to treatment. Forcing research is difficult but you can gin public support for it. Yet advocates seem to have jumped over research using an obtuse backwards kind of tautology: proponents argue that the drug's illegality is preventing research, so it must be made legal for the sake of research and the best way to achieve that is to call it a medicine, so that we can legalize it and find out if it's an effective medicine. This basically makes the public a phase II human trial for medical marijuana under the banner of compassionate medical care. That is not a scientific progression for a solid medical treatment. I recognize that it is possible that there is an undercurrent of legalizing recreational marijuana. Or this philosophy may be a result of previous dismissal of marijuana by the medical community. No matter the origin, promoting medical marijuana as a treatment has become almost a belief system.

If we approach this medication critically what do we know?
  1. There is evidence that medical cannabis may help with psychiatric complaints and with subjective complaints like insomnia, pain.

  2. There is a mountain of poor-quality evidence claiming support for other uses for cannabis, but without good data to back up those assertions.

  3. Both proponents and opponents lack a good scientific methodology; they propose ideological, unsupported, and implausible claims.

  4. The actual efficacy and safety of medical cannabis is very murky.

  5. Its benefit as a medical treatment is unclear.

In my opinion, widespread adoption of medical marijuana is premature. Marijuana needs to be removed from US Schedule I so that research is possible. More research is needed. It may be an effective, safe pain medication. Currently the jury is out on that. Finding out the answer to that question is only possible if both the proponents and the opponents of medical marijuana can find some common ground around scientific inquiry.

I cannot in all good conscience recommend medical cannabis except in palliative terminal cases. It just has too many unknowns. Given the evidence I am just as likely to be prescribing a big fat placebo with a dissociative element as an effective medical treatment. It needs more research... period, the end. Currently it is not a treatment—it is a guess. It needs well-controlled duplicated studies; it needs the active ingredients and their interactions to be identified. We need to know what is an effective dose and what's a toxic one. It needs all of this before you can call this a treatment. I demand that level of knowledge before I give anything to patients. You can't cut corners because you believe something is effective. You can't base success of a treatment on patient satisfaction when you are dealing with medications that have recreational uses. Getting drunk may help you deal with pain, but it won't fix anything. I won't offer my patients a bottle of Jack Daniels anymore than I will offer them a bag of cannabis. It is just not a medical treatment. I demand more of my medical treatments and so should you.

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by Stephen Propatier

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