In general, alcohol abuse and dependence are parts of a chronic, progressive, relapsing disorder that advances in stages from experimentation to dependence (Heilig and Egli, 2006; Jupp and Lawrence, 2010; Koob, 2009; Koob and Le Moal, 2008; Koob and Volkow, 2010; Spanagel, 2009; Volkow and Li, 2005). In general, the disease progresses from rewarding, euphoric and positive-reinforcement aspects of alcohol intake that drive the disease-process in early stages to the dysphoric and associated negative-reinforcement aspects that drive the process in later stages. Ethanol is positively reinforcing by producing a euphoria/high or a perceived positive sense of well-being (e.g., increases in perceived confidence). Ethanol is negatively reinforcing by removing dysphoria (e.g., anxiety) or a negative sense of well-being (e.g., hangover and physiological withdrawal). Once dependence is acquired, ethanol’s negative-reinforcement aspects overshadow ethanol’s positive-reinforcement aspects making the disease very difficult to treat. It is noteworthy that progression from experimentation to dependence is not linear in nature, with individuals often returning to earlier stages of the disease process before advancing to final stages of dependence. Therefore, in addition to considering the age-of-onset and pattern of drinking, effective treatment must also take into account the progressive nature of the disease.
