Patterns of sustained heroin abstinence amongst long-term, dependent heroin users: 36 months findings from the Australian Treatment Outcome Study (ATOS)

AimsTo determine patterns of past month, 12 month and sustained 36 month heroin abstinence.MethodsAs part of a longitudinal cohort study, 429 heroin users re-interviewed at 36 month follow-up for the Australian Treatment Outcome Study (ATOS).ResultsThe proportion who had sustained heroin abstinence since baseline declined from 14% at 12 months to 8% at 36 months. The proportion who reported abstinence over the preceding 12 months, however, increased significantly from 14% at 12 months to 40% at 36 months. There were no significant gender differences in the proportions reporting sustained 36 month abstinence. Females, however, were significantly more likely to have maintained abstinence over the 12 months preceding 36 month follow-up. Independent predictors of sustained abstinence over 36 months were fewer treatment episodes since baseline, not committing crime at baseline and higher levels of global psychological distress.ConclusionsDespite a decline in the proportion who had maintained complete heroin abstinence over 36 months, there were substantial increases in 12 month abstinence patterns. The results illustrate the importance of stable treatment retention.