Self-reported ecstasy use: the impact of assessment method on dosage estimates in recreational users

While research has associated recreational ecstasy use with negative outcomes, there remain a number of methodological limitations of human studies. The present study examined the impact of self-report methodology on lifetime ecstasy dosage figures using three estimation methods: a single question estimation, a context-based timeline method and a quantity–frequency method. We used a repeated measures design, testing 38 participants aged over 18 years who reported using ecstasy on ten or more occasions. Methodology was found to impact on estimations made, with the timeline method producing higher figures than the single question. While single question and timeline estimations were positively correlated, there was no relationship between either of these methods and the quantity–frequency method. The present findings are in keeping with indications in the alcohol and other drug literature that the use of contextual memory cues increases accuracy of recall as indicated by higher estimations, and that quantity–frequency methods may not adequately assess variability in lifetime drug-use patterns.