I wonder whether the home secretary opened the PowerPoint presentation on the dangers of ecstasy that she was sent by the man the papers describe as the "UK's greatest expert" on the drug. If she did, was she impressed?
Professor Andy Parrott from Swansea University has emerged as the most powerful academic opponent to the view expressed by the Advisory Council on the Misuse of Drugs that MDMA or ecstasy should be downgraded in their recent report [322Kb PDF].
He tried to get the medical journal The Lancet to publish his criticism of the ACMD's analysis, but says that they turned him down flat. Instead, he made his presentation to the committee and then sent his slides [69Kb PDF] to Jacqui Smith.
He argues that the Chair of the ACMD, Professor David Nutt, has made a number of "extremely serious errors" in papers on the relative dangers of ecstasy and seeks to demolish the committee's argument with his own "extensive knowledge".
Here is the key slide from his presentation in which he lists the dangers of ecstasy and his sources:
This sounds pretty frightening. Ecstasy kills scores of people a year, damages their brains, makes them more likely to attack people and makes them monsters behind the wheel.
But a quick check of the sources suggests that Professor Parrott may be making some errors himself.
• Deaths: "40-70 per year in the UK"
• Source: Schifano, F et al (2006): Ecstasy (MDMA, MDA, MDEA, MBDB) Consumption, Seizures, Related Offences, Prices, Dosage Levels And Deaths In The UK (1994-2003) [91Kb PDF]
• ACMD estimate: 10-17 caused by ecstasy
The Schifano paper does provide a table which at first glance appears to support Parrott's claim that ecstasy kills many more people in Britain than the figure estimated by the ACMD.
But death mentions are not the same thing as deaths by ecstasy, as Schifano himself makes clear:
"The number of cases identified here were actually 'mentions' of ecstasy on death certificates, ie no information was available in respect to ecstasy and concomitant other drugs' dosage, post mortem reports, toxicology results and setting characteristics.
Ecstasy inclusion on those documents submitted to General Mortality Registers did not necessarily mean that this drug directly 'caused' the death, but that ecstasy (MDMA, MDA, MDEA, MBDB) was found at post-mortem and/or was identified by toxicological screening. A number of methodological problems can contribute to make it difficult to interpret the role ecstasy plays in the so-called 'ecstasy related' deaths and especially so if accurate information is not available."
In a 2007 editorial written by Prof. Parrott himself (Ecstasy Versus Alcohol: Tolstoy And The Variations Of Unhappiness), he notes that the death data are pretty meaningless:
"In relation to annual deaths, Schifano et al. (2006) suggested an annual UK death rate of around 40-70/year, although they noted the many difficulties in arriving at these estimates, since most fatalities are in ecstasy polydrug users. Indeed all the functional and structural data on recreational ecstasy/MDMA is confounded by other drug and non-drug factors."
• Brain damage: "Most robust finding was a reduction in serotonin transporter density"
• Source: Cowan, RL (2007): Neuroimaging Research In Human MDMA Users: A Review
• ACMD: "unsure" about ecstasy's long-term effects on the brain
Actually, Cowan concludes something rather different about his research on MDMA ecstasy's effect on the brain:
"The current state of neuroimaging in human MDMA users does not permit conclusions regarding the long-term effects of MDMA exposure."
• Aggression: "Increased mid-week"
• Source: Curran, HV et al (2004): Empathy And Aggression: Two Faces Of Ecstasy? A Study Of Interpretative Cognitive Bias And Mood Change In Ecstasy Users / Hoshi, R et al (2006): An Investigation Into The Sub-Acute Effects Of Ecstasy On Aggressive Interpretative Bias And Aggressive Mood: Are There Gender Differences?
• ACMD: no evidence that ecstasy causes "interpersonal violence"
The Hoshi work involved "participants processing sentences that could be interpreted as either aggressive or neutral and subsequently remember them in a recognition test. Ecstasy users show a bias toward interpretation of ambiguous material in an aggressive manner when compared to controls 4 days after ecstasy use".
I am not an expert on this kind of analysis, but I do wonder whether we need better evidence to conclude that ecstasy users are significantly more likely to beat someone up on Wednesday nights than their responses to sentence construction.
• Car driving: "Can be 'extremely dangerous'"
• Source: Brookhuis, K et al (2004): Effects Of MDMA (Ecstasy), And Multiple Drugs Use On (Simulated) Driving Performance And Traffic Safety
• ACMD: did not find evidence that ecstasy causes road deaths
The Brookhuis paper Professor Parrott cites does not suggest ecstasy makes car driving extremely dangerous. In fact, it says:
"Driving performance in the sense of lateral and longitudinal vehicle control was not greatly affected after MDMA, but deteriorated after multiple drug use."
And the line about the dangers is in this sentence:
"Driving under the influence of MDMA alone is certainly not safe; however, driving back (home) after a dance party ("rave") where MDMA users regularly combine MDMA with a host of other drugs can be described as extremely dangerous."
• Cardiac: "MDMA has profound cardiovascular effects in humans and animals"
• Source: Perrine, SA et al (2008): Cardiac Effects Of MDMA On The Metabolic Profile Determined With (1)H-Magnetic Resonance Spectroscopy In The Rat
• ACMD: poor evidence to suggest ecstasy causes heart damage
The paper cited actually says this:
"Acute exposure to MDMA has profound cardiovascular effects on blood pressure and heart rate in humans and animals."
Professor Parrott chose not to include those key words in his slide.
No-one disputes that taking ecstasy involves risk (see my previous post). Indeed, it seems that we are in urgent need of better research on the long-term effects of MDMA. And the Advisory Council made it clear that ecstasy is a harmful drug and deserves to be listed within Class B.
Its conclusions are based on the largest-ever systematic review of any drug in Britain. Everything is posted online for further academic review. The ACMD did not come to its conclusions alone; the work was scrutinised by the Health Technology Assessment programme.
Naturally, I've tried to contact Professor Parrott to discuss the points above with him, but he hasn't responded to my calls.
Professor Parrott wrote a personal letter to the home secretary urging her not to listen to the ACMD. Instead, he suggests an "independent review" of the committee's findings.
"As one of the leading international experts in this area, I would be willing to undertake such a review", he writes.
Update 26 Feb: Professor Parrot has sent me this document [30Kb PDF] with his response which I'm happy to include here.