In fact, this hypothesis was tested using data from a recent clinical trial.34 Individuals with the CT genotype demonstrated greater cue-elicited craving when treated with placebo but not when treated with a medication designed to dampen the mesocorticolimbic reactivity to cues. During a 12-week trial, alcohol-dependent individuals with the CT genotype demonstrated significant reductions in drinking during treatment with the active medication compared with placebo treatment. Conversely, individuals with the TT genotype responded equally well to the combination of placebo and psychosocial treatment vs active medication and psychosocial treatment. These findings are similar to those with the DRD4 variable number of tandem repeats reported by Hutchison and colleagues.34 Notably, χ2 tests indicated that these 2 loci were not linked in this sample.
