Alcohol dependence has two basic components: positive effects primarily attributed to ethanol stimulated release of dopamine in the reward centers of the brain and negative effects of anxiety and depression that occur after cessation of drinking (Koob, 2013). The reward system in the brain includes the mesocorticolimbic dopamine system and extended amygdala, which intersect in the nucleus accumbens shell. Within this system, ethanol increases the release of dopamine in the shell of the nucleus accumbens, which is directly associated with the rewarding effects of ethanol consumption (McBride, 2002; McBride and Li, 1998) reviewed in Koob (2013). Serotonin modulates the effect of ethanol on dopamine release via the 5-HT3 receptor (Campbell et al., 1996; Campbell and McBride, 1995; Engleman et al., 2008; Wozniak et al., 1990).
