The TPQ scores are associated with DRD2 TaqI A polymorphisms in healthy American boys [58], Taiwanese subjects with anxiety, depression and alcohol dependence [47], methamphetamine-dependent Americans [59], Finns [60], Germans [61], Russians and Tatars [62] and heroin-dependent Malaysians [15], whereas non-association was observed in healthy French and Austrian subjects [63, 64] and in depressed patients in a New Zealand population [65]. Here, DRD2 is linked to alcohol dependence.