Considerable evidence suggests that during dependence, allostatic dysregulation of motivational systems and negative reinforcement learning may promote the development of excessive alcohol consumption (Heilig et al., 2006; Heilig et al., 2010; Koob & Le Moal, 2008; Walker et al., 2008; Walker et al., 2010). This theory of allostatic dysregulation builds upon earlier theories of homeostasis (Solomon & Corbit, 1974) that describe the role of opponent processes in motivational and affective behaviors. In essence, when a drug induces a positive hedonic state, a compensatory negative hedonic state will follow. In cases of chronic alcohol or drug exposure, the positive hedonic state decreases and the negative hedonic state increases due to both within- and between-system changes that involve the recruitment of brain stress and negative affect circuits (Heilig & Koob, 2007; Koob2009a; Koob & Le Moal, 1997). Thus, when alcohol use is terminated, the neuroadaptations underlying these negative emotional states remain and the organism learns that continued ingestion of drugs self-medicates the symptoms associated with withdrawal (Heilig et al., 2006; Heilig et al., 2010; Markou et al., 1998). The combined results of
