Some things never change. This month, a new report came out from the federally funded Marijuana Potency Project declaring THC levels in marijuana to be at an all time high.


Scare stories about high-potency marijuana are almost as old as the war on marijuana itself. Prohibitionists for decades have warned people that the contemporary version of the drug is "not your father's marijuana" (of course, they wanted to arrest your father for his low-grade stuff as well). Bush drug czar and technological hepcat John Walters likes to refer to modern marijuana as though it were an entirely different drug altogether: marijuana 2.0, he calls it.


The news hook for this latest in what has become an annual ritual of phony hand wringing over rising marijuana potency is that the samples tested have reportedly edged over an average of 10 percent for the first time. I say "reportedly" because, although the National Institute on Drug Abuse publicized the report's findings to the media, they have not posted the report online and have so far refused to provide us with a copy.


Anyway, drug warriors love to exaggerate small increases in marijuana potency and make vague proclamations linking them to increases in marijuana’s potential danger. Of course, vague proclamations are all they have because there isn't a shred of evidence that increased potency raises marijuana's danger in any way. It's not more toxic, it's not more addictive, and it kills the same number of people low-grade marijuana does – zero.


My colleague, Bruce Mirken, appeared on CNN's "Anderson Cooper 360" to discuss this nonsense May 14, pointing out the obvious fact that, if anything, high potency marijuana is probably safer if you agree marijuana's chief danger lies in the harms related to inhaling smoke. When the marijuana is more potent, users smoke less, just as people typically drink a much smaller quantity of bourbon than of beer. Thus, higher-potency marijuana doesn’t necessarily mean users take in more THC – they just take in less smoke.


For most, this is a matter of common sense. Marijuana users seek a particular effect and stop once they've achieved that effect, just as most drinkers do. Of course, inexperienced users of either drug may find they've overshot that desired effect. The main difference between the two is that inexperienced marijuana users won't die from their error as inexperienced drinkers may.


Cooper had Walters on the same segment in a separate interview. Confronted with Bruce's point that higher potency marijuana doesn't necessarily lead to increased smoke intake, Walters responded, "There is no evidence of that."


But there is. In a study titled "Vaporization as a Smokeless Cannabis Delivery System: A Pilot Study," published in May 2007 by the journal Clinical Pharmacology and TherapeuticsUniversity of California researchers looked at smoking and vaporization using marijuana of 1.7 percent, 3.4 percent and 6.8 percent THC.


Although the high-strength marijuana was four times as potent as the weakest, it produced a peak plasma THC level only about 20 percent higher. This, the researchers wrote, suggests that either less is absorbed at the higher potency levels or there is "self-titration of THC intake," meaning "smokers adapt their smoking behavior to obtain desired levels of THC." Among the evidence for self-titration, researchers found that their subjects tended "to take more puffs at lower THC concentrations" – despite having been given a fairly regimented smoking procedure to follow. Similarly, the subjective "high" reported by participants was only modestly more intense at 6.8% THC than at 1.7 percent.


If you're concerned that the man in charge of federal marijuana policy for the past decade would be so out of touch with the research on the subject, don't be – he knew. We know this because NORML's Paul Armentano pointed it out to him when Walters was making up the same lie last year, and he sent him the article.


Of course, if defenders of marijuana prohibition were truly worried about THC levels in marijuana, then they should favor regulating the drug and requiring manufacturers to label the product’s potency, just as we do with alcohol.


I guess we'll just have to wait and find out what they say after next year's report.



Dan Bernath is the Marijuana Policy Project’s assistant director of communications, Email him at