Depression, memory problems, anxiety, mood fluctuation, poor concentration, infections, tremors/twitches, and weight loss are all more common among people who have used Ecstasy more often. In a survey of 282 Ecstasy users, memory problems attributed to the drug were reported by 19% of novice users (1–9 occasions), 52% of moderate users (10–99 occasions), and 73% of heavy users (100+ occasions). The incidence of psychobiological problems attributed to Ecstasy use increases directly with the number of times it has been used.
Among 49 undergraduate volunteers, self-reported Ecstasy use closely matched MDMA traces found in hair samples. Both self-report and hair analysis predicted lower happiness and higher stress ratings. Self-reported use, but not hair analysis, was also linked to lower tension. The findings suggest the Internet can effectively complement traditional laboratory studies on recreational drug effects.