Saturday, 18 February 2012

The War on Drugs - Medicinal Marijuana

Though I tend to only enter into political debates with my closest friends, I cannot help but comment on a clip that I found on YouTube. In short, Republican presidential candidate Mitt Romney is answering a question from an audience member regarding medicinal marijauna.

The clip:

And the quote:

"...And you know you know you hear that story, people who are sick needing medicinal marijuana, but marijuana is the entry drug for people trying to get kids hooked on drugs. I don't want medicinal marijuana, there are... synthetic forms of marijuana that are available for people that need it on prescription. Don't open the doorway to medicinal marijuana"

To begin with, marijuana has been used for medicinal purposes for a number of reasons. Primarily, marijuana (and select cannabinoids present in marijuana) have been shown to decrease the incidence and strength of nausea, and to stimulate hunger. These effects benefit those on chemotherapy or who are afflicted with AIDS, and has also been shown to have positive effects on patients with glaucoma. 

That marijuana has been used for medical purposes is of no surprise. Records from as far back as 4000 BCE have shown that marijuana has been used for medicinal purposes by the Chinese, during the Neolithic period. Even in relatively modern times, tinctures and extracts of marijuana have been used to treat pain and headaches, to aid in sleep, and so on.

Perhaps what irritates me most with Romney's comment on medicinal marijuana is that he refers to the spurious notion that marijuana is a gateway drug. For those unfamiliar, the Gateway Drug Theory proposes that the use of "softer" recreational drugs, like marijuana, alcohol and tobacco, leads to a dramatically increased risk of a user moving on to "harder" drugs like heroin, cocaine and so on. It is also posited that as a user moves on to "harder" drugs, that they will also move on to a life of crime in order to fund their drug habit. There are variations of the Gateway Drug Theory, but for now we will deal with Romney's concern, that marijuana (and other "soft" drugs) are used to hook children on "harder" drugs.

I won't deny that research into the Gateway Drug Theory is still ongoing, and that for every article criticising this theory, another article comes out shortly thereafter criticising the criticism, and so on. That being said, there are some fairly big holes in this theory. Namely, the theory itself relies on the post hoc ergo propter hoc logical fallacy. In the context of the Gateway Drug Theory: 

An individual tried a "soft" drug like marijuana. They then moved on to use a "hard" drug. Therefore, use of the "soft" drug caused them to use a "hard" drug at a later date. 

To put it another way, in this case correlation does not explicitly imply causation.

The main criticisms of the Gateway Drug Theory are detailed on the wikipedia page linked above. In summary, the more salient criticisms are:
  • Due to curiosity and/or the pleasure-seeking behaviour of humans, some people will actively seek out and experiment with drugs. So-called "gateway" drugs are simply those that are more readily available;
  • In the event that an individual seeks out recreational drugs that are illegal, they will be exposed to the black market for drugs. In this case, they will be exposed to readily available "harder" drugs. Therefore, the availability of different recreational substances on the black market is a possible cause for moving on to harder drugs, rather than use of a "soft" drug leading directly to the use of a "hard" drug, regardless of circumstance;
  • Hyperbole and misinformation surrounding the nature of gateway recreational drugs causes teenagers and adults alike to distrust all anti-drug messages, thereby resulting in the individuals trying other, "harder" drugs at a later point;
  • Drug dealers that have access to "harder" drugs will, due to the nature of their wares, be unwilling to engage in sales with those unfamiliar with gateway drugs. Therefore, those that buy from these dealers will already be acquainted with the "harder" drugs.
Another aspect of Romney's argument is that marijuana is addictive. Now, this is a tricky thing to deal with, as two separate forms of addiction exist. One is physical addiction/dependence, whereby continued use of a drug results in a physical need to continue usage, and has neurobiologic underpinnings. The other is psychological addiction/dependence, in which there is a strong behavioural aspect to the addiction.

The dependence potential of marijuana is interesting, in that it is reported as being less addictive than alcohol, tobacco, heroin, cocaine and select other recreational drugs. Nutt et. al (2007) provide an interesting comparison between various licit and illicit recreational drugs, with the following graph a concise summary of their findings:

In addition, a fascinating study by Coffey et. al.(2002) reveals that the symptomatology of marijuana dependence is poorly defined. Overall, marijuana dependence is a known phenomenon (recognised in the DSM-IV, section 304.30), and involves both physical and psychological dependence on the drug in question. 

In short, the argument that Romney uses is poorly constructed. It relies on the fact that marijuana is a gateway drug, which is still under debate. In addition, it posits that marijuana is addictive (which it is). What is not recognised is that a large number of recreational drugs (including legal drugs like tobacco and alcohol) have a higher dependence potential than marijuana.

I will cede, however, that the development of synthetic preparations of cannabinoids is a good thing. This allows dosage to be controlled, thereby ensuring that an adequate dose is provided to the patient. Furthermore, in patients that may require medicinal marijuana but do not want to experience the psychoactive effects of marijuana, well, the synthetic preparations of the cannabinoids present in marijuana provides a good middle ground.

In the end, contentious issues like the War On Drugs and medical marijuana will continue to be debated. Indeed, this is an area that I will come back to in the future. And as for Mr. Romney, well, he personifies my gripe with the aversion that many politicians have towards evidence-based policies, and those politicians that happily invoke populism and puritanism in order to win votes. Unfortunately, this is a phenomenon that is not limited to the United States of America, and seems to creep into politics, whether in Australia or abroad.

Thanks for reading,

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