The New Zealand Arrestee Drug Use Monitoring (NZ-ADUM) study monitors levels of alcohol and other drug use, and related criminal offending, among police detainees in Whangarei, Auckland, Wellington and Christchurch central city police stations (see Wilkins et al., 2010b). NZ-ADUM tracks key drugs of concern, including methamphetamine, cannabis, opioids, pharmaceutical medicines and new psychoactive substances (NPS) (so called ‘legal highs’), as well as the emergence of entirely new drugs.