Patterns of heroin use in the methadone programme in Sydney, 1986-1987

A study was undertaken to examine patterns of heroin use by clients attending New South Wales Health Department methadone maintenance units in Sydney. The study group included those clients who commenced taking methadone between January 1986 and January 1987 and who remained on individual programmes until December 1987. A total of 16 800 urinalysis results from 346 clients were examined. Data were correlated vertically so as to examine heroin use by all clients beginning with their first dose of methadone. Contrary to expectation, the data indicate that heroin use did not decline as a function of time. The data were further examined within a numerically stable group, which had been sub-classified according to the number of morphine positive urine samples over a period of 12 months. These data indicated the existence of two major groups; those whose continued use of heroin could be described as occasional and another heavy using group. The latter constituted 51% of the study population and contributed almost 90% of the morphine positive urines. The use of urinalysis data to identify the heavy and occasional-user groups could assist in a study to define those factors which could be responsible for the continued use of heroin whilst on a methadone maintenance programme.