Last week, a new cannabis-causes-violence study had serious echoes of 1930s Harry Anslinger and Reefer Madness. The Times characterized it as, "Scientists find link between cannabis, psychosis and violence," while the Daily Mail headline proclaimed, "Smoking cannabis DOES make people more violent." The Canadian researchers behind the Frontiers in Psychiatry study said in their own words, "Our results suggest a unidirectional association between cannabis use and violence."
How did the study come up with these results? The five researchers tracked 1,136 recently discharged psychiatric patients for nearly a year with 10-week follow-ups, and they asked about incidents of substance use and violent behavior. The research claims those who "used cannabis at each follow-up periods were 2.44 times more likely to display violent behaviors."
A closer look at the study, however, suggests a more appropriate summation might be, "Propagandist BS stinks worse than the Cheese n Chong strain." How so?
First, the "unidirectional association" suggests that cannabis motivates violence but not the other way around. That may or may not be true, but it's not the pertinent question, and it sidesteps the more relevant association between cannabis and mental health disorders. Even if violent behavior does not motivate cannabis use, most researchers agree that mental health disorders—often a primary contributor to aggressive outbursts—can motivate self-medicating substance use. Likewise, the type of disorders that necessitate psychiatric hospitalization often correlates with higher rates of physical violence. Nearly a quarter of patients were institutionalized schizophrenics, but the study suggests that cannabis—not severe schizophrenia—prompted the violent acts? It begs the question, what were the researchers smoking?
This brings us to point number two. Half the patients suffered from primary affective disorder, which is a form of depression. The other half consisted of patients with schizophrenia, personality disorders and/or substance use disorders, a group of patients arguably more prone to self-medicate with cannabis and act aggressively during a psychiatric relapse. Rather than draw a causal line from cannabis to violence, consider that self-medication and violent outbursts are simply different manifestations of the same mental health disorders. In that case, the same disorders increase the likelihood of violence and self-medicating use, and this would skew the data and compromise a correlation-based finding.
The third point highlights a contradiction in observational evidence and arguably reinforces the self-medication argument. Per the findings, the psychiatric patients who smoked cannabis had higher rates of violence than those who were drinking and doing blow. So to take this study at face value, the researchers claim a stoned schizophrenic is more dangerous than a drunk or coked-up schizophrenic. These hosers obviously don't get out a lot.
Point four involves a statistical issue. The study utilized follow-ups at 10-week intervals. Reported cannabis use went from 16.5 percent at the first follow-up to 5.4 percent at the fourth, while self-reported violent behavior went from 23.3 percent at the first follow-up to 14.1 percent at the fourth. The two-thirds reduction in cannabis use was not followed by a similar reduction in violence. In fact, the rate of violence at the fourth follow-up is nearly double what it should be if the reduction percentages matched. If one were to follow the study's lead in drawing conclusions based on correlation, one might argue that cannabis was found to lower rates of violence.
The fifth point involves the sources themselves. Let's start with the mainstream media outlets that were so quick to push the study. News Corp, of Rupert Murdoch and Fox News fame, owns The Times, and that information speaks for itself in terms of credibility. A few rings of hell lower, the Daily Mail is a right-wing tabloid that published an anti-refugee cartoon, a "Just ONE cannabis joint can bring on schizophrenia" headline, a homophobic profile on Boyzone singer Stephen Gately mere days after his death, and an anti-semitic profile of a Labour leader's father that the Jewish Chronicle said recalls the paper's "Hitler-appeasing past and temporary admiration for the [Fascist] Blackshirts."
So the Frontiers study has that media support going for it, which is nice.
Daily Mail and The Times support aside, the Frontiers collection of journals has its own share of controversy, including its inclusion on a blacklist of questionable publishers and in this 2016 study on predatory publishing. In the past, Frontiers studies have suggested vaccinations cause autism but that HIV does not cause AIDS. Criticisms of the publishing company can be found here, here and here.
Then there's the Frontiers business model. The authors must pay to get their work published in a Frontiers title, and its peer-review process has been heavily criticized. Case in point, dozens of editors were fired in 2015 for "holding up the publication of papers" going through the peer-review process. Per Science, "The editors say Frontiers' publication practices are designed to maximize the company's profits, not the quality of papers, and that this could harm patients."
Frontiers describes itself this way: "Our grand vision is to build an Open Science platform where everybody has equal opportunity to seek, share and generate knowledge, and that empowers researchers in their daily work." You can be part of that grand vision for a fee, and the cannabis-causes-carnage researchers likely paid $1900 to have their study published. To be clear, pay-to-play scholarship doesn't always mean the findings are inaccurate, and studies published in Frontiers benefit from no-cost access to the research, but questionable conclusions involve a major caveat when found in such for-profit science journals.
The cannabis-violence study is only a few days old, but British right-winger Kathy Gyngell already said this "definitive" research highlights how the government is "seriously negligent" in not enforcing cannabis prohibition to the max. She then asks why there is no government effort to highlight the dangers of cannabis, which is a bit like asking why MSNBC doesn't criticize President Trump.
"Where is the public health campaign on the risks of cannabis? If ministers had any sense, they would know that we cannot afford this public health and safety crisis," added Gyngell, who previously blamed the rise of Donald Trump on feminists and compared the "hysteria" around sexual abuse claims to the Salem witch trials. So the researchers have her support going for them, too.
This cannabis-harm study has serious credibility issues, yet anti-cannabis figures clap like trained seals at any research that supports a crackdown. The "definitive" cannabis-causes-violence research was anything but, and it epitomizes the need to question the veracity of clinical findings as much as we do media headlines, especially when public support comes from Gyngell types who cling to their prohibitions like junkies gripping a Percocet bottle. The anti-cannabis forces are losing the prohibition argument, which makes them desperate for any research that helps justify their unjustifiable cause. This means the public must be ever-so diligent in shoveling away the bullshit.