RATIONALE: Acamprosate is a proven effective intervention in the treatment of alcohol dependence. However, acamprosate prevents lapses or relapses only in a minority of patients. An important question, therefore, is whether there is a specific subgroup of patients who respond particularly well to acamprosate.OBJECTIVES: To identify predictors of acamprosate efficacy. Based upon the available evidence and hypotheses about the mechanisms underlying acamprosate's effects on drinking behavior, the following variables were considered to be potential positive predictors: high physiological dependence at baseline, negative family history of alcoholism, late age-of-onset, serious anxiety symptomatology at baseline, severe craving at baseline, and female gender.METHOD: Potential predictors of acamprosate's efficacy were analyzed in a pooled analysis of data from seven randomized placebo-controlled trials involving a total of 1485 patients with alcohol dependence. Outcome is measured in terms of cumulative abstinence duration (CAD), continuous abstinence (ABST), and time to first relapse (TFR).RESULTS: CAD and ABST were predicted by baseline measures of craving and anxiety, as well as by study and treatment condition. Acamprosate efficacy was not differentially associated with any of the predictor variables. Importantly, the hypotheses were rejected despite the large sample size and sufficient statistical power.COMMENT: The most straight-forward clinical implication of this study is that acamprosate can be considered as a potentially effective pharmacotherapy for all patients with alcohol dependence. The effect size of acamprosate alone is, however, moderate. Some evidence indicates that the combination of acamprosate with naltrexone or disulfiram leads to substantially better outcomes.