Findings concerning possible genetic moderators of response to acamprosate have been reported [99], but are preliminary. Additionally, other findings suggest the influence of a DRD4 variable number of tandem repeats (VNTR) polymorphism on response to olanzapine, a dopamine antagonist that has been studied as an experimental treatment for alcohol problems. Olanzapine was found to reduce alcohol-related craving those with the long-repeat VNTR (DRD4 L), but not individuals with the short-repeat version (DRD4 S; [100,101]). Further, a randomized trial of olanzapine led to significantly improved drinking outcomes in DRD4 L but not DRD4 S individuals [100].
