Cannabis is one of the oldest medicines on the planet, but predispositions for and against the plant tend to taint everything the public hears about its supposed benefits and dangers. Moreover, opinions on medical cannabis can be extreme. Countless parents, desperate to help a child dying from a hundred-plus seizures per day, relocated to states that legalized medical cannabis. This led to the term “medical marijuana refugees.” Yet, some who hear of such plans report the parents to law enforcement, and child services “save” the children by stripping them from their parents. Sadly, that is how extreme the medical cannabis fight has become, and it complicates clinical research like few compounds in history. Bias is one of many reasons it is difficult to judge cannabis studies, as are the following four examples.
1. Media Clickbait
In July 2016, The Journal of the American Medical Association Psychiatry published a study using data from the long-term Dunedin study in New Zealand that examined the physical effects of long-term cannabis use. Its findings produced headlines like “Cannabis use associated with periodontal disease” (American Dental Association) and “Long-Term Pot Use Tied to Gum Disease in Study” (Health Day). So, what did the study actually say? Using Dunedin tracking data that goes back more than two decades, the authors concluded that chronic cannabis consumers had equal or better physical health in all metrics except for gum health, making cannabis as bad for you as not flossing yet beneficial in other healthy ways. Moreover, the actual cause of the gum disease could be chronic smokers who, after smoking each night, regularly neglect dental hygiene regimens, which suggest no direct link between cannabis and gum health.
Now re-read the headlines above. They might be good clickbait, but they do not accurately reflect the main findings of the study, and they promote the stigmatization of a medically viable plant among individuals who often only read headlines. This epitomizes the difficulty in trusting the media to summarize health studies properly.
2. Conflicting Conclusions
The study referenced above also highlights how complex and contradictory findings can be. While most anti-cannabis advocates would never quote the positive findings in that study, they are all too quick to embrace the findings in another study by the same lead researcher, Dr. Madeline Meier. Four years earlier, she led a similar team who used Dunedin data to conclude that early cannabis use leads to permanent neuropsychological decline and the potential loss of IQ points (eight points on average). To this day, anti-cannabis advocates regularly quote these findings from the 2012 Proceedings of the National Academy of Sciences of the United States of America study, yet the story doesn’t end here.
Nine months after the 2012 Proceedings study, a different group of researchers published a rebuttal in the same journal that said socioeconomic status, not cannabis, was the likely cause. The authors wrote, “Although it would be too strong to say that the results [of the Meier study] have been discredited, the methodology is flawed and the causal inference drawn from the results premature.” In a press release for the study, the lead author added that wrongly blaming cannabis for serious health issues “may detract focus from and awareness on other potentially harmful behaviors.” An Oxford University reviewer reiterated the same conclusion, arguing, “The current focus on the alleged harms of cannabis may be obscuring the fact that its use is often correlated with that of other even more freely available drugs and possibly lifestyle factors. These may be as or more important than cannabis itself.”
Translation: People who wrongly blame cannabis for a host of evils are likely harming public health.
3. People Believe What They Want to Believe
In November 2016, this writer spoke with an anti-cannabis advocate who cited the 2012 study about IQ reduction, and when I mentioned the other studies, the person denied they even existed. I offered to send links, to which she countered, “I know it’s true no matter what the other studies say.” This anecdotal example is by no means rare when it comes to medical opinions on cannabis studies. There are many, many conflicting conclusions, and it is important to take all findings, for or against medical cannabis, with a grain of salt… but especially those studies that are against.
“There’s just so much noise and chatter because there’s so many harm studies being funded, much more so than benefit studies,” explains Dr. Sunil Aggarwal of Doctors for Cannabis Regulation (DFCR), speaking with PRØHBTD in 2016. “Just the sheer number where people are trying to justify harm—of course, there’s risks for cannabis use, just like there’s risk for any substance use. When we’re talking about medical indications, we stand with many of our colleagues in medicine who believe the evidence shows that cannabis does have bona fide, specific medical uses. It’s been proven by repeated, high-quality trials.”