Objectives: To describe the prevalence of lifetime and 12-month stimulant use disorders in the Australian population, and to compare the prevalence estimates from a population survey with prevalence estimates derived using indirect methods.

Design and setting: Data were drawn from the 2007 National Survey of Mental Health and Wellbeing, which sampled 8841 residents of private dwellings in Australia in 2007.  Interviews were conducted by lay interviewers using the Composite International Diagnostic Interview.  The NSMHW asked about stimulant use in five categories: (i) amphetamine/speed, (ii) methamphetamine/base/ice, (iii) ecstasy, (iv) cocaine, and (v) any stimulant.  Lifetime stimulant use was assessed by asking whether respondents had used any of these drugs (i) at any time, and (ii) more than 5 times in their lifetime. Respondents who reported lifetime stimulant use on more than 5 occasions were asked whether they had used any stimulant in the past 12 months.

Main outcome measures: Lifetime and 12-month rates of stimulant use and stimulant use disorders (abuse, dependence) diagnosed according to the Diagnostic and statistical manual of mental disorders, 4th edition.

Results: Lifetime prevalence of stimulant use disorders was 3.3%, and 12-month prevalence was 0.6%, equating to more than 97,000 Australians.  Nearly half of those who had used stimulants on more than 5 occasions met criteria for a lifetime disorder.  More than 8% of men aged 16-29 years met criteria for a lifetime stimulant use disorder.  Prevalence estimates were consistent with recent estimates using indirect methods.

Conclusions: Stimulant use disorders affect a significant number of Australians, and are most common in the age groups at greatest risk for development of psychosis.

See also editorial by R McKetin and DI Lubman commenting on these findings, p.565-566.