Compulsivity in alcoholism can derive from multiple sources, including enhanced incentive salience, engagement of habit function, and impairment in executive function. However, underlying each of these sources is a negative emotional state that may strongly impact on compulsivity. The development of the negative emotional state that drives the negative reinforcement of addiction has been defined as the “dark side” of addiction (Koob and Le Moal 2005, 2008) and is hypothesized to be the b-process of the hedonic dynamic known as opponent process when the a-process is euphoria. The negative emotional state that comprises the withdrawal/negative affect stage consists of key motivational elements, such as chronic irritability, emotional pain, malaise, dysphoria, alexithymia, and loss of motivation for natural rewards, and is characterized in animals by increase in reward thresholds during withdrawal from all major drugs of abuse. Two processes are hypothesized to form the neurobiological basis for the b-process: loss of function in the reward systems (within-system neuroadaplation) and recruitment of the brain stress or anti-reward systems (between-system neuroadaptation; Koob and Bloom 1988; Koob and Le Moal 1997). Anti-reward is a
