Correcting NIDA Director Nora Volkow

The new Monitoring the Future Survey results for 2013 were released recently.

In discussing the new data in a video released on YouTube, Dr. Nora Volkow, the director of the National Institute on Drug Abuse, said this: “If we compare the numbers that were, for example, in 2000 regular users, and now in 2013, we have seen increases in those numbers. But in 2000, at the 2000 level of 9 THC was at least half of the levels that we observe now, at least half. So that means that not just were there less kids taking the drug regularly, but even those that were taking it regularly were taking a much less potent drug.”

It almost sounded like she was asserting that THC levels have doubled but that's not what she said. She did definitely assert that in 2000, cannabis was much less potent.

The short version of this report is, she was wrong. Way wrong. And this isn't just some political hack, or an uninformed blogger. She's the director of the government's National Institute on Drug Abuse, she's supposed to be the science person on drugs. That's not acceptable.

Here's how badly she got it wrong. Let's look at what's known. I make these data available through my website at drugwarfacts.org, in the marijuana section, where you can find a table of average THC levels of seized samples of cannabis as reported by the University of Mississippi's Potency Monitoring Project.

These are the only data on this, they're the same data Nora Volkow has. The Project stopped testing domestic samples a few years ago, the last domestic cannabis data are from 2010. Samples of non-domestic cannabis – imports from Mexico, Jamaica, Canada, and so many other countries – continue to be tested, but only preliminary data for 2012 are currently available.

Average THC potencies are given for two grades of cannabis: low-end commercial grade – what they call simply “marijuana” - and high-end sinsemilla-type cannabis. The overall combined average they report includes a few samples of ditchweed, so let's just stick with specific data for those two types, and since 2010 is the last year with domestic data, let's use it for comparison.

In 2000, non-domestic commercial grade marijuana averaged 5.10% THC. The non-domestic sinsemilla type averaged 12.87%. Domestic commercial grade marijuana averaged 3.96% THC, and domestic sinsemilla type averaged 12.72%.

In 2010, non-domestic commercial grade marijuana averaged 6.69% THC. Non-domestic sinsemilla type averaged 12.81% THC. Domestic commercial grade marijuana averaged 2.79% THC, and domestic sinsemilla type averaged 11.84%.

So only one category shows an increase in average potency from 2000 to 2010 is for non-domestic commercial grade cannabis – an increase of 31%, going from 5.1 to 6.69% THC. The others all show decreases, in fact the average THC of domestic commercial grade dropped by 29.5%.

Sure, there are fluctuations: In 2011, the average THC in non-domestic commercial marijuana was down to 5.6%, the average for non-domestic sinsemilla type was 13.47%. They stopped testing domestic samples in 2010, remember, and for what it's worth those numbers were much lower in 2009, when domestic commercial averaged 2.43% THC and domestic sinsemilla type averaged only 7.37%.

So, Nora Volkow's statement? Maybe not a flatout lie, but inaccurate and misleading at best.

Eventually, hopefully, we'll get complete data for 2012, and when that's available, you'll find it at drugwarfacts.org.