DRD4 and alcohol abuse: Polymorphic variants of the DRD4 gene appear also to influence pharmacological efficacy in the treatment of Alcohol Use Disorder: it was demonstrated that olanzapine, an atypical antipsychotic, which is a DRD4 and DRD2 antagonist with also high affinity for serotonergic, muscarinic, histamine, and α-1-adrenergic receptors, reduced craving elicited by alcohol cues only in DRD4 L carriers, but not in DRD4 S carriers [80,81].