DRD2 and substance dependence: Interestingly, these observations align with early research by Gold’s group, which hinted at the potential therapeutic efficacy of bromocriptine, a D2 agonist, in combating cocaine abuse and dependence.29 Unlike the DRD2 Taq A1 allele, which is associated with decreased D2 receptor levels, the main variant, DRD2 Taq A2 allele, is characterized by normal D2 receptor levels, possibly offering protection against psychostimulant misuse and abuse.30