“It turns your brain into Swiss cheese… “

“For lack of a better term, it turns your brain into Swiss cheese… puts holes in it, does permanent brain damage, irreversible, irreversible from the very first time.”

These are the words of a Drug Enforcement Administration (DEA) official talking about taking Ecstasy on an ABC special ‘Ecstasy Rising’. Shocking stuff! Enough to make people stop and reconsider taking the drug. Especially when accompanied by this striking poster campaign by the National Institute on Drug Abuse (NIDA) in the US.

The images in this poster were taken from a NIDA funded study carried out by Dr Una McCann and colleagues at Johns Hopkins University. They had scanned the brains of 14 abstinent MDMA users (MDMA being the active compound in Ecstasy) and 15 controls who had never used MDMA before. This group found that “MDMA users showed decreased global and regional brain 5-HT [serotonin] transporter binding compared with controls. Decreases in 5-HT transporter binding positively correlated with the extent of previous MDMA use.” In other words, they found that the more Ecstasy someone had taken the more damage there was to the brain’s serotoninergic neurons.

However, this study, which both the DEA and NIDA used as part of their anti-Ecstasy campaign for many years, has been criticized widely by many scientists. For example; Dr Stephen Kish stated in a review of the study that “because of the serious methodological concerns in the PET measurement related to the high scatter of the values for the control and drug groups and lack of test–retest results, the data derived from the McCann investigation can only be considered, at most, ‘semiquantitive.’

The general consensus from the scientific community is that the results of this study quite simply do not stand up when subjected to scrutiny. Despite this, the poster showing images from the study continued to be used long after it was discredited.

Science has authority. It has authority because the scientific method is a process which, in theory, prevents political and personal bias. It has authority because peer-review ensures that theories are subjected to scrutiny by other experts in the field. This post is not really about Ecstasy, or even about the wider drugs debate. It is a reminder of the power that science has, and that we should this power wisely. Political pressures should not factor in the scientific process.

The selective use of images from a potentially flawed study is a prime example of where the authority that science has to persuade has been misused. The impact of this was summed up excellently by an opinion piece in New Scientist at the time:

“There are no ironclad certainties in science. All theories and observations have their critics. And just because a finding appears in a peer-reviewed journal doesn’t make it the last word: journals exist as much to enliven debate as to get it right. So on one level, our inquiry into the quality of the scientific evidence suggesting ecstasy harms brain cells is perhaps unsurprising.

What we found is that certain high-profile studies claiming ecstasy causes lasting damage are based on flawed brain scans. But so what? Other teams will eventually repeat the experiments with better techniques. The truth will out. And in the meantime, does it matter if the evidence is shaky as long as it sends a suitably grim warning to people taking the drug?

In this case it matters a lot.  These scans are not minor bits of academic science.  They can be selectively presented to make it look as though ecstasy users have blotchy holes in their brains.  It’s a potent visual message that’s been seized on by drugs education campaigns and continues to guide those who set drugs penalties.  That might just be defensible if the findings were simply disputed or uncertain.  But our investigation suggests the experiments are so irretrievably flawed that the scientific community risks haemorrhaging credibility if it continues to let them inform public policy.”

References:

 McCann et al (1998) Positron emission tomographic evidence of toxic effect of MDMA (“Ecstasy”) on brain serotonin neurons in human beings. The Lancet. 352 (9138): 1433 – 1437.

Kish (2002) How strong is the evidence that brain serotonin neurons are damaged in human users of ecstasy? Pharmacology, Biochemistry and Behavior. 71: 845–855.

 

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