Underreporting of ecstasy use among high school seniors in the US

National surveys suggest ecstasy (3,4-methylenedioxymethamphetamine [MDMA]) use has decreased substantially among adolescents in the US since 2001; however, the recent phenomenon of "Molly" (ecstasy marketed as "pure MDMA") may be leading to underreporting of use as not all users are aware that "Molly" is a form of ecstasy.

We examined 2014 data from Monitoring the Future, a nationally representative survey of high school seniors in the US (N=6250, modal age: 18). Three randomly distributed survey forms asked about ecstasy use, and one included "Molly" in the definition. Self-reported lifetime, 12-month, and 30-day ecstasy use were compared to determine whether including "Molly" in the definition was associated with higher prevalence or frequency of use.

The form including "Molly" in the definition had significantly higher prevalence than the two (combined) forms that did not. Lifetime use (8.0% vs. 5.5%) and 12-month use (5.1% vs. 3.6%) were significantly higher with "Molly" in the definition. Lifetime prevalence remained higher with "Molly" in the definition when controlling for correlates of ecstasy use; however, 12-month use did not. Differences in prevalence were associated with lifetime occasions of use, with lower concordance between forms at lower levels of lifetime occasions (e.g., 1-2 times). Survey form was not related to number of times used among more frequent users.

Prevalence of ecstasy use appears to be underestimated when "Molly" is not included in the definition of ecstasy/MDMA. Surveys should include "Molly" in the definition of ecstasy to more adequately assess prevalence of use.