Objective: To determine incidence and patterns of natural course of ecstasy/stimulant/hallucinogen (ESH) use and disorders as well as cohort effects in a community sample of adolescents and young adults. Method: Cumulative incidence and patterns of ecstasy use and disorders were examined in a prospective longitudinal design (mean follow-up period = 42 months) in a representative sample (N = 2446) aged 14-24 years at the outset of the study. Patterns of DSM-IV defined ESH use, abuse and dependence were assessed with the Munich Composite International Diagnostic Interview (M-CIDI). Results: (1) Cumulative lifetime incidence for use of ESH at second follow-up: 9.1%, 1.0% for abuse, 0.6% for dependence; (2) men used and abused ESH more often than women; (3) the younger birth cohort (1977-81) tended to start earlier with substance (ab)use compared to the older birth cohort (1970-77); (4) use of ESH was associated with increasing rates of concomitant use of other licit and illicit drugs; (5) the majority of the lifetime ESH users without disorder had stopped to use these substances and not consumed them during the 12 months preceding the second follow-up; (6) those who had stopped to take ecstasy and related drugs at follow-up also took other illicit drugs less often than those who continued to consume ESH. Conclusions: Use of designer drugs is widespread in our sample, but the probability of developing use disorders is fairly low (1.6%). The majority of the ESH users stopped their use spontaneously in their twenties (80% of the prior users without disorder, 67% of the prior abusers), but 50% of those that once had fulfilled DSM-IV criteria of dependence continued to use these substances.