title: Young adults' trajectories of Ecstasy use: a population based study.
abstract: Young adults' Ecstasy use trajectories have important implications for individual and population-level consequences of Ecstasy use, but little relevant research has been conducted. This study prospectively examines Ecstasy trajectories in a population-based sample. Data are from the Natural History Study of Drug Use, a retrospective/prospective cohort study conducted in Australia. Population screening identified a probability sample of Ecstasy users aged 19-23 years. Complete data for 30 months of follow-up, comprising 4 time intervals, were available for 297 participants (88.4% of sample). Trajectories were derived using cluster analysis based on recent Ecstasy use at each interval. Trajectory predictors were examined using a generalized ordered logit model and included Ecstasy dependence (World Mental Health Composite International Diagnostic Instrument), psychological distress (Hospital Anxiety Depression Scale), aggression (Young Adult Self Report) and contextual factors (e.g. attendance at electronic/dance music events). Three Ecstasy trajectories were identified (low, intermediate and high use). At its peak, the high-use trajectory involved 1-2 days Ecstasy use per week. Decreasing frequency of use was observed for intermediate and high-use trajectories from 12 months, independently of market factors. Intermediate and high-use trajectory membership was predicted by past Ecstasy consumption (>70 pills) and attendance at electronic/dance music events. High-use trajectory members were unlikely to have used Ecstasy for more than 3 years and tended to report consistently positive subjective effects at baseline. Given the social context and temporal course of Ecstasy use, Ecstasy trajectories might be better understood in terms of instrumental rather than addictive drug use patterns.
authors.affiliation: Queensland Alcohol and Drug Research and Education Centre, School of Population Health, The University of Queensland, Herston Rd, Herston, QLD 4006, Australia. a.smirnov@uq.edu.au
authors.forename: Andrew
authors.initials: A
authors.lastname: Smirnov
authors.forename: Jake M
authors.initials: JM
authors.lastname: Najman
authors.forename: Reza
authors.initials: R
authors.lastname: Hayatbakhsh
authors.forename: Maria
authors.initials: M
authors.lastname: Plotnikova
authors.forename: Helene
authors.initials: H
authors.lastname: Wells
authors.forename: Margot
authors.initials: M
authors.lastname: Legosz
authors.forename: Robert
authors.initials: R
authors.lastname: Kemp
mesh_terms: D019969:Amphetamine-Related Disorders / Q000523:psychology*; D001294:Attitude to Health; D016000:Cluster Analysis; D006213:Hallucinogens; D006801:Humans; D018817:N-Methyl-3,4-methylenedioxyamphetamine; D010465:Perception; D011446:Prospective Studies; D012189:Retrospective Studies; D012959:Socioeconomic Factors; D013315:Stress, Psychological / Q000209:etiology; D055815:Young Adult
chemical_list: D006213:Hallucinogens; D018817:N-Methyl-3,4-methylenedioxyamphetamine
keywords: Drug dependence; Drug use trajectories; Early adulthood; Ecstasy (MDMA); Maturational factors; Social environment