Abstract
Background and aims: MDMA (3,4-methylenedioxymethamphetamine or "Ecstasy") is the fourth-most used illicit substance globally. While previous research found links between MDMA use and mental health outcomes, the direction and nature of this relationship remain unclear. This study assessed whether MDMA use in early adulthood increases the risk of anxiety or depression in mid-30s.
Design: A longitudinal, population-based study using doubly robust inverse probability treatment weighted regression analysis, a contemporary confounder adjustment technique, to examine the relationship between MDMA use in early adulthood (age 20-29) and subsequent anxiety or depression at age 35.
Setting: Victoria, Australia.
Participants: Data were drawn from the Victorian Adolescent Health Cohort Study (VAHCS), which began in 1992 with a statewide representative sample of 1943 Year 9 students (aged 14-15) from 44 Victorian schools. This paper uses data collected from wave 2 to wave 10 (ages 15-35).
Measurements: Across waves 7-9 (ages 20-29), MDMA use was categorised as any use, persistent use (none, one wave, two or more waves) and frequent use (none, infrequent, frequent). Wave 10 (age 35) outcomes were 12-month diagnoses of major depressive disorder and anxiety disorders assessed using the Composite International Diagnostic Interview (CIDI).
Findings: There was little evidence linking any pattern of MDMA use in early adulthood with depressive disorders by the mid-30s; however, compared with non-MDMA users, the adjusted odds of an anxiety disorder were higher in those who reported past 12-month MDMA use [odds ratio (OR) = 1.73, 95% confidence interval (CI) = 1.12-2.68), persistent MDMA use at two or more waves (OR = 2.05, 95% CI = 1.07-3.94), as well as infrequent (OR = 2.11, 95% CI = 1.14-3.92) and frequent MDMA use (OR = 2.56, 95% CI = 1.15-5.71).
Conclusions: MDMA use (3,4-methylenedioxymethamphetamine or "Ecstasy") in early adulthood appears to be associated with increased odds of anxiety disorders but not depressive disorder by the mid-30s.