Longitudinal analysis of street Ecstasy content

A topic that arises every now and again, particularly when I am discussing Ecstasy-related medical emergency and death, is the nature of the psychoactive ingredients in Ecstasy tablets. For definitional purposes, I consider 3,4-methylenedioxymethamphetamine (MDMA) to be what is considered by the vast majority of consumers to be canonical “Ecstasy”.
It is reasonably well-established in the peer reviewed literature and the ecstasydata.org harm reduction effort that some fraction of Ecstasy that is distributed contains non-MDMA psychoactive compounds either in addition to, or replacement for, MDMA. There are, however, some nagging questions because the published data are spotty. One topic of interest to me is that of selection bias. Tablet analyses are published either from samples turned in by Ecstasy consumers or those obtained by law enforcement seizures. In the former case there is a reasonable case to be made that perhaps Ecstasy found to result in suspicious subjective effects on the user are submitted to harm reduction sites preferentially. In the case of law enforcement seizure, well, the ones that got caught are by definition not on the street for sale. And you can make up a whole list of other caveats about why the published analyses might not accurately reflect the picture of what is actually being consumed.
A recent paper doesn’t nail down every complaint but at least it compares samples submitted willingly and unwillingly by the consumer.

Vogels, N., Brunt, T., Rigter, S., van Dijk, P., Vervaeke, H., & Niesink, R. (2009). Content of ecstasy in the Netherlands: 1993-2008 Addiction Epub ahead of print Oct 5 2009; DOI: 10.1111/j.1360-0443.2009.02707.x

The Netherlands set up a Drug Information and Monitoring System (DIMS) in 1992 to receive and analyze samples of street drugs. The present paper reports on the results from 1993 to 2008, an impressive longitudinal dataset. The data on seized tablets only runs from 2004-2006 and is a bit unusual for the class. The paper reports that tablets were seized from consumers at club venues and “turned over to the police” who thereafter submitted them to the DIMS for analysis. So a little different from the usual samples seized in primary police actions but still, we can address the difference between voluntary and involuntary tablet sourcing. This should go some way to determining if voluntary submissions are disproportionally of “suspicious” subjective properties; if true, the available data would overestimate the amount of street Ecstasy that contains non-MDMA ingredients.
Although roughly similar in nature, the seized samples differed from the submitted samples in several particulars. Significantly more (chi-square) tablets in the seized sample contained only MDMA (86% vs 79%) and the voluntarily submitted samples had more low (70 mg MDMA) content tablets. From what I can tell from the number of tablets analyzed (6033 submitted vs 737 seized), yes this analysis only includes the same subset of years for the voluntary samples. The identity of the non-MDMA constituents was described as being similar between the two samples.
Returning to descriptive stats from the submitted samples, MDMA-only samples ranged from about 70-90% across the years of analysis. This dipped to 60% in 1997 and there seems to be a stepwise decrease over the interval of 2005-2008. This coincided with a notable uptick in the inclusion of a specific compound, mCPP. Other than this, the most consistent non-MDMA pschoactive was caffeine. Ephedra and methamphetamine were frequently observed in the mid-late 1990s. PMA, a frequent hypothesized suspect in medical emergency, was apparently only seen in 2001-2002.
MDMA content is an additional dataset of interest, especially since this is less frequently reported in the available reports. Tablets containing 36-105 mg of MDMA were predominant in most years, about evenly split around the 70 mg mark. Higher content tablets (106 mg +) appear to have gradually gained marketshare from about 2001 onwards. In 2008 about 22% of samples contained 106-140 of MDMA and 8% contained over 140 mg.
All in all a nice addition to the knowledge base. Voluntary and involuntary submissions are roughly alike with a bit of support for a bias toward low/high MDMA content and nonMDMA psychoactives in voluntary samples. As one might expect, but this gives a look at the magnitude of the effect. The longitudinal sampling is interesting to see and gives a good picture of the percentages of MDMA-only across time (higher than certain MDMA fans seem to acknowledge when it comes time to assess medical emergency cases) and the relative proportions of specific contaminants (certain baddies are quite rare). I thought the rise and fall in popularity of methamphetamine, PMA, ephedrine and mCPP as additives was intriguing as well.
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Literature Cited
Vogels, N., Brunt, T., Rigter, S., van Dijk, P., Vervaeke, H., & Niesink, R. (2009). Content of ecstasy in the Netherlands: 1993-2008 Addiction DOI: 10.1111/j.1360-0443.2009.02707.x