This analysis and critique was written in response to the critique written by Cole and colleagues (Cole et al. 2002). Morgan expressed agreement with Cole and colleaguesŐ that overly simplistic conclusions are sometimes drawn from MDMA research. As an example of such overstatement, he notes that his own research found that cannabis use, and not ecstasy use, better explained a higher rate of psychological problems in ecstasy users. Nevertheless, he believes Cole and colleagues did not give more careful consideration to studies that attempt to solve some of the problems faced by retrospective studies of polydrug users, as when researchers attempt to control for use of other drugs by comparing ecstasy users with polydrug users. Since some ecstasy users report having taken up to 15 ecstasy tablets on one occasion, and others report using an average of 2 to 4 tablets per occasion, Morgan believes that some ecstasy users may be taking enough ecstasy to produce neurotoxic effects. However, in making these calculations, Morgan assumes that interspecies scaling can provide an accurate estimate of the neurotoxic dose of MDMA in humans, a point of contention (see Vollenweider et al. 2001). Morgan refers to his own research findings of increased impulsivity in ecstasy users as evidence that regular ecstasy use may have long-term effects. The author does not believe that findings of reduced cognitive function in ecstasy users are due to the beliefs held by MDMA researchers.