This paper reviews studies of psychotropic drug use in Australia, analyses results from the Australian Health Surveys and compares the findings with those from other countries. It identifies subpopulations with high rates of drug use, which may consequently be at greater risk of drug-related harm. The levels of consumption of psychotropic agents in Australia were estimated from the results of studies conducted in community and institutional settings between 1970 and 1986. In the absence of more recent data national prevalence rates were derived from analysis of data provided by the Australian Health Surveys (AHS) of 1977-1978 and 1983-1984, and comparisons were made with rates available from other countries. While the prevalence of current and frequent use of drugs for nervous conditions was found to have decreased in most age groups over this period, it was consistently higher in females than in males, and increased with age. An analysis of the 1983-1984 AHS data revealed that the consumption of "medicines for nervous conditions" fell by 35% but that no change occurred in the prevalence of persons taking sleeping medicines. This fall appeared to occur in both rural and urban populations. Further analysis of data relating to the consumption of hypnotic agents revealed that changes occurred in the patterns of use within age and gender subgroups. Significant differences were observed between Australian States in consumption rates of sleeping medicines (chi 2 = 282.2; df = 7; P less than 0.01) and of medicines for nervous conditions (chi 2 = 289.7; df = 7; P less than 0.01). There were high rates of use of medicines for sleep in South Australia and of medicines for nervous conditions in Queensland. The prevalence of use of both drugs for sleep (rs = 0.71; P less than 0.05) and drugs for nervous conditions (rs = 0.77; P less than 0.05) was related to the rate of consultations with doctors. Preliminary surveys of various non-British subpopulations including Aborigines were inconclusive. These results have implications for reducing the harm associated with the use of psychotropic agents, particularly hypnotics and drugs for nervous conditions, in Australia.