A few studies to date have investigated genetic polymorphisms in the context of pharmacotherapies for alcohol dependence. One of such studies has found that a polymorphism of the µ-opioid receptor gene (OPRM1) was associated with clinical response to naltrexone among alcohol dependent patients (Oslin et al., 2003). The relationship was such that individuals with at least one copy of the variant allele (the A118G SNP of the OPRM1 gene) showed lower relapse rates and longer time to return to heavy drinking when treated with naltrexone (Oslin et al., 2003). These findings have been recently replicated in the COMBINE Study (Anton et al., 2008), such that carriers of the G allele receiving Medication Management (MM) showed a significant decrease in heavy drinking days, as compared to homozygotes for the A allele. In addition, 87% of carriers of the G allele had a good clinical outcome to naltrexone + MM, as compared to 55% of homozygotes for the A allele; and the groups did not differ in their response to MM plus placebo (Anton et al., 2008). And overall, naltrexone was superior
