Genetic variation may result in differences in the constitution and functioning of neural mechanisms that underlie the phenotypic manifestations of risk for AUD. Numerous studies have linked structural and functional brain alterations to genetic variations associated with neurotransmitter/transporter synthesis, receptor organization, and brain growth (Frodl et al. 2004, 2008; Nemoto et al. 2006; reviewed by Lipsky and Marini 2007; Peper et al. 2007). Further, genetic variations associated with risk for AUD have also been recognized as etiological factors in ADHD, conduct disorder, depression, and anxiety disorders. Therefore, it is likely that there are specific genetic mechanisms of risk for AUD, as well as common genetic diatheses that exist between AUD, conduct disorder, depression, anxiety, ASPD, and ADHD. Genetic factors may mediate the neural circuitry comprising the externalizing and internalizing pathways to AUD.
