NDARC Technical Report No. 28 (1995)
Summary
This paper attempts to estimate the potential demand for methadone maintenance treatment in Australia. It begins with a review of the strengths and weaknesses of different methods of estimating the number of regular or dependent heroin users in Australia, namely, sample surveys of drug use, multiplier methods, and capture-recapture estimates. Because no single method of estimation is superior to all of the others, a number of methods (those last used in 1988 on data for the period 1984-1987) were applied to data from the period 1988-1992 to estimate changes in the number of regular or dependent heroin users in Australia over the period 1984 to 1992. The number of heroin dependent users currently in methadone maintenance treatment were compared with the estimated number of dependent heroin users in the population to indicate what proportion of current users were in methadone treatment.
The estimates of the number of heroin users in Australia in 1988-1992 indicate a fair degree of uncertainty. Nevertheless, all estimates all showed an increase on the estimated number of dependent heroin users in Australia in 1984-1987. The increase in the multiplier estimates of the number of heroin users in methadone maintenance treatment probably reflects an increase in the availability of methadone treatment during the period. This is less likely to be true of any of the other estimates.
The median estimate for the various methods in each time period shows an increase from approximately 34,000 (range 25,000 - 86,000) in 1984-1987 to approximately 59,000 (range 49,000 - 150,000) in 1988-1992. Population rates calculated on the midpoints of these range of estimates suggest that the population prevalence of dependent heroin use has increased from 4.5 to 7.2 per 100,000 between 1986 and 1990. On these estimates, the proportion of heroin users currently in methadone treatment has increased from approximately 17% in 1987 to approximately 30% in 1992. Even if we allow that not all dependent heroin users are interested in methadone maintenance treatment, there is still probably substantial unmet demand for this form of treatment.