in addiction diagnosis and management would require the collection of behavioral and genetic measures and their use against a research foundation that is today largely nonexistent. However, one of the first examples of pharmacogenetic prediction of treatment response in the addictions is a common functional missense variant of the μ-opioid receptor (OPRM1 Asn40Asp). As mentioned, this variant also appears to be associated with altered reward function.56 In several studies, naltrexone, a μ-opioid receptor antagonist, was observed to augment abstinence and good therapeutic outcome in recovering alcoholics. Carriers of the Asp40 allele were highly likely to show clinical improvement when treated with this drug.134,135 Similarly, CHRNA5Asn398Asp106 and DBH have been reported to influence smoking cessation treatment, and would seem to indicate the existence of subgroups of addicted patients identifiable via genetic testing.
