Originally appearing at http://www.guardian.co.uk/theobserver/2011/apr/03/letters-cameron-scargill-comparison. The Observer and the public continue to wrestle with the question whether use of the stimulant drug ecstasy causes brain damage, especially as animal data suggest that ecstasy might damage nerve cells in the brain that use serotonin as a neurotransmitter. Professor Andrew Parrott and 39 colleagues cite in “Ecstasy is far from harmless” (Letters) the results of our brain imaging study (Brain 133:1779-97, 2010) as an investigation that has “indicted” “serotonergic neurotoxicity” in human ecstasy users. Assuming that the term “indicated” rather than “indicted” was meant , Professor Parrott’s statement is an over-interpretation of our findings, as the observed low levels of a brain serotonin neuronal marker could be explained by loss only of the marker, without actual loss of or physical damage to brain serotonin nerves. Our brain imaging data are certainly consistent with the possibility that ecstasy might cause damage to brain serotonin nerves, but the case for the human has not yet been proven in the scientific literature. On March 27, 2010, Prof. Andrew Parrot (Swansea University) wrote a letter to the editor criticizing Prof. John Halpern’s (Harvard) recent study finding no association between heavy recreational Ecstasy use and cognitive damage. Below, Prof. Stephen Kish of the University of Toronto points out that in his rush to attack the study, Parrott actually misinterpreted the results of Kish’s own Ecstasy study, undermining Parrott’s critique. Debate may be important for the progress of science, but so is accuracy.