13 October 2016

Here’s the introduction to the piece. We recommend you link through to the full article

Authored by: Adrian Devitt-Lee

Mark Twain once said, “A lie can travel half way around the world before truth even gets its boots on.” When it comes to reporting on cannabis science, in many ways we’re still traveling barefoot.

The recent revelations about the Sugar Research Foundation bribing Harvard researchers to mislead the public on the role of sugar in heart disease is a particularly egregious example of bad science, but outright deception is not the only way that bogus science makes its way into the public dialogue [1]. Researcher bias and a desire for sensational discoveries can also lead to misinformation—especially when it comes to controversial topics like cannabis. Journalists often compound these distortions by hyping dubious science and ignoring research that calls into question conventional wisdom.

Faulty Assumptions

In assessing the veracity and significance of scientific reports, several questions are paramount: What data is being measured? How does the data relate to the phenomenon being studied? What conclusions are drawn from the data? Are the conclusions justified or do they distort or overstate what the data implies?

Consider, for example, a May 2014 article in Pharmacology, Biochemistry and Behavior examining the addictive potential of cannabinoids. The article begins by acknowledging the difficulties in getting rats to self-administer THC, marijuana’s major psychoactive component: “Because ∆9-tetrahydrocannabinol (THC) has been a false negative in rat intravenous self-administration procedures, the evaluation of the abuse potential of candidate cannabinoid medications has proven difficult . . . . Clarification of underlying factors responsible for the failure of THC to maintain self-administration in cannabinoid-trained rats is needed” [2].

Note the assumptions at play here. From the start it is assumed that THC is addictive, and contradictory evidence is rationalized to fit that assumption. The authors acknowledge that THC is not addictive in what they refer to as “the ‘gold standard’ in preclinical assessment of abuse liability,” and so one reasonable conclusion is that THC is not addictive. Alternatively, one can conclude that this “gold standard” model does not capture the complex nature of addiction to cannabinoids. Yet neither of these possibilities are mentioned.

Because THC wouldn’t cooperate, the authors utilized a different compound in an experiment that sought to replicate and extend an addiction model that had been successfully performed, but only in a few labs. (Repeating experiments across different lab groups is very important in scientific research.) This model involved the trained self-administration of WIN55,212-2, a synthetic cannabinoid, by rats. WIN55,212-2 (or WIN55, for short) is a potent activator of CB1 and CB2, the same cannabinoid receptors that THC stimulates. But unlike with THC, rats can be trained to self-administer WIN55, which is not derived from marijuana. “The effects of WIN may be more comparable to the frequently abused synthetic cannabinoids, often referred to as K2 and spice, than to marijuana,” University of Pittsburgh scientists reported in a different journal [3].

This is not to say that the authors of the WIN55 experiment intended to deceive or that their research is without merit. The authors do not step beyond their data to make claims about THC or cannabinoids more generally. But from the first sentences of this article, there is an inconsistency between the authors’ assumptions and the data presented.