Effect of early and late compliance on the effectiveness of acamprosate in the treatment of alcohol dependence

Background: The aim of this study is to assess the influence of early and late compliance of acamprosate on attendance and abstinence duration in the treatment of alcohol dependence. Methods: Individual patient data of 2,305 patients from 11 randomized controlled trials comparing acamprosate (n = 1,128) with placebo (n = 1,177) were used to predict early and late compliance and to study the effect of early and late compliance on attendance and abstinence duration using regression analysis and structural equation modeling. Results: Early compliance was predicted by baseline motivation to become fully abstinent and baseline abstinence (R2 = .26); late compliance was predicted by early compliance (R2 = .13); treatment discontinuation was predicted by young age, marital status, compliance, and treatment condition (R2 = .26); and abstinence duration was predicted by motivation to become fully abstinent early compliance and the interaction of early compliance and treatment condition (R2 = .27). Structural equation modeling showed that abstinence duration was significantly associated with motivation at baseline, late compliance, and treatment condition (Goodness of Fit Index [GFI] χ2/df = 1.56; Parsimonious Goodness of Fit Index [PGFI] = 0.69). Conclusions: Motivation to become fully abstinent and abstinence at the start of treatment are important for early compliance. Early compliance in turn predicts late compliance. Late compliance, in combination with motivation to become fully abstinent, and treatment condition (acamprosate vs. placebo) predict duration of abstinence. This suggests that motivational interventions directed toward full abstinence motivation and abstinence at the start of treatment are crucial for both compliance with acamprosate and successful treatment outcome