MPP Update #27

By Dan Bernath

"Doctors: Pot Triggers Psychotic Symptoms," Associated Press, April 30

"Cannabis Chemical Curbs Psychotic Symptoms, Study Finds," The Guardian, May 1

It's hard to believe, but the two headlines above refer to the same event, a conference in Britain featuring research about marijuana and mental illness. What gives?

News media reports about marijuana sometimes resemble that parable about the three blind men who argue about what an elephant looks like. One man feels only the elephant's leg and concludes that elephants look like trees. Another feels only the tail and concludes elephants look like rope. The third feels only the trunk and concludes elephants look like snakes.

They all get it wrong, because no one is seeing the big picture.

To some degree, these problems are built into the way the news media work. Coming up with a headline – or even an entire story – about a series of scientific studies is a lot like describing an elephant after examining only a tusk.

The story accompanying the first headline focuses on a study that examined MRI images of marijuana users' brains during intoxication. It's long been known that marijuana intoxication sometimes causes effects that can resemble symptoms of psychosis - hallucinations or paranoid delusions, for example - in some users, and the MRI images gave some new clues about how these effects may be generated. But the study didn't find anything to suggest marijuana causes psychosis in people with no preexisting tendency.

That's not surprising: The fact that there's never been a documented increase in diagnosed psychosis or schizophrenia during periods of increased marijuana use suggests that any such effect is weak if it exists at all.

The headline in the Guardian story refers to another study presented at the conference that found that cannabidiol (CBD) – another compound found in marijuana – may actually be an effective treatment for schizophrenia. Previous studies have indicated that CBD can mitigate some of the unwanted effects of THC - marijuana's main psychoactive compound - including those feelings of paranoia or anxiety that bear some resemblance to psychosis.

At least the debate among the three blind men isn't further muddied by personal agendas about what an elephant ought to look like. By contrast, a great deal of the research examining marijuana and mental illness is fueled by ideologues anxious to find any connection between the two that might inflate the potential danger posed by marijuana.

A century of research hasn't turned up any solid evidence that marijuana causes psychoses such as schizophrenia. It probably does trigger or aggravate symptoms in some people with existing psychotic tendencies, a very different thing. But some scientists with government ties have muddied that distinction, and media reports continue to misunderstand and misrepresent what the research actually says.

Marijuana alarmists have found this a pretty effective technique for another pervasive, but discredited, assertion: that today's marijuana is dramatically more potent, and therefore more dangerous, than it was a generation ago.

This whopper was most recently revived in a statement from the Office of National Drug Control Policy last month sounding the alarm that marijuana's THC content had doubled in the past 20 years. The ONDCP must have known that nobody would notice or care that they had previously claimed marijuana was 30 times more potent.

Moreover, according to the National Institute on Drug Abuse's Nora Volkow's ominous, carefully worded statement, this may very well explain an increase in "the number of medical emergencies involving marijuana."

News organizations dutifully transcribed this nonsense, to the point where Reuters was forced to issue a correction acknowledging that there was no evidence indicating that marijuana caused any medical emergencies, though clearly that was Volkow's implication.

The more important question ought to be whether increased potency really does mean increased harm. After all, THC is nontoxic, and marijuana has never caused an overdose death. Plus, research indicates marijuana users seek a target effect and instinctively consume less marijuana if the potency is higher, just as drinkers consume less vodka than they would beer.

There may actually be some legitimate concerns regarding increased THC levels in marijuana. If it's true that cannabidiol counteracts some of the undesirable effects that THC induces in some users, then it could be true that marijuana cultivated to enhance its THC content - which likely has an increased ratio of THC to CBD - might increase those effects.

What the drug warriors won't acknowledge is that the system of prohibition makes it much harder to address any such legitimate issues. Products produced and sold illegally aren't labeled for potency or tested for purity as, for example, alcoholic beverages are. If marijuana were legally regulated, producers could be required to indicate the level of THC, CBD, or any other components right on the label, just as a bottle of beer, wine or liquor now indicates the alcohol content.

Instead, they look at selected facts and conclude prohibition is the answer. I'm afraid to ask what they think an elephant looks like.

Dan Bernath is the Marijuana Policy Project’s assistant director of communications, www.mpp.org. Email him at dbernath@mpp.org.