AIMS: To describe and assess trends in the use of hallucinogens and other adjunct drugs over a 5-year period. DESIGN: Repeated-measures cross-sectional survey. SETTING AND PARTICIPANTS: Annual magazine-based survey targeting people who use drugs in dance contexts. MEASUREMENTS: Lifetime use prevalence (ever used); age of first use; current use prevalence (any use within the last month), and extent of use within the last month (number of days used) for LSD, psilocybin, ketamine, GHB and nitrates. FINDINGS: Prevalence increases for psilocybin, ketamine, GHB and nitrates use have been detected, with a sharp recent rise in current psilocybin use in 2002-2003 contrasting with more gradual and comprehensive evidence of increased ketamine use throughout the period 1999-2003. The declining prevalence of LSD use in general population surveys is replicated in this sentinel population study. CONCLUSIONS: The rise in prevalence of hallucinogen and other adjunct drugs identified among dance drug users may be mirrored by wider prevalence increases among young people with a consequent need to study these trends carefully and to develop effective interventions, where required.