A few studies have investigated the pharmacological and genetic underpinnings of craving for alcohol. For example, a study by Hutchison et al64 has found that individuals with the “long” variant (7 or longer repeat allele) of the D4 dopamine receptor gene (DRD4 VNTR) displayed higher craving after consumption of alcohol, as compared with the placebo beverage. In addition, a pharmacological trial of olanzapine in a nonclinical sample found that individuals with the long allele of the DRD4 VNTR demonstrated greater reduction in craving after alcohol consumption during the medication condition, as compared with individuals with the short allele.65 These results were later expanded using a clinical sample, in which patients with the long allele of the DRD4 VNTR experienced greater reductions in craving for alcohol and reduced alcohol consumption during the course of treatment, as compared with individuals with the short allele.66 The fact that craving has been linked to specific biological mechanisms and has both etiological and clinical implications demonstrates its utility as an endophenotype for studying genetic and pharmacological factors associated with alcoholism and its treatment.
