Abstract
Patterns of illicit and non-prescribed drug use among a cohort of 100 patients in methadone maintenance treatment were tracked over a 6-month period. While there were no statistically significant changes in alcohol or heroin use, there were significant increases in the frequency of crack cocaine and cannabis use. Use of non-prescribed methadone had also increased. Twenty-one percent reported non-prescribed methadone use at follow-up who had not done so at the first interview, with increases also in the mean quantities used. Non-prescribed methadone use at the second interview was strongly associated with the amounts of both methadone and diazepam prescribed at each of the data collecting points.