From opioid maintenance to abstinence: a literature review.

It appears that the literature on agonist maintenance therapies for opioid dependence pays more attention to outcomes during, rather than after, treatment. This review aims to (a) estimate to what extent opioid abstinence can be expected from former maintenance patients, (b) examine possible relationships between patient and treatment characteristics and abstinence rates and (c) assess the need for research in the field of abstinence-orientated maintenance treatment in general, and time-limited buprenorphine maintenance treatment in particular. Database searches supplemented by cross-references resulted in 12 studies included in the review. The studies were mostly naturalistic follow-up studies of former methadone maintenance patients, authored by US researchers in the 1970s. Buprenorphine was used in only one of the studies, and then as a transition between methadone and abstinence. There were considerable variations in definition and assessment of abstinence. Pooled abstinence rates ranged from 22% to 86%. The single factor associated most frequently with abstinence was voluntary participation in detoxification programmes with eligibility criteria ('therapeutic detoxification'). When 'therapeutic detoxification' was compared to 'non-therapeutic detoxification' the pooled abstinence rates were 48% and 22%, respectively. Abstinence-orientated maintenance therapy may be suitable for a subgroup of patients, but there is a substantial need for research updates.