Chunk #20 — 1 Definitions and Conceptual Framework for Reward Deficit in Alcoholism — 1.1 Theoretical Framework: Motivation, Withdrawal, and Opponent Process
An acute elevation in brain reward thresholds was observed during repeated acute withdrawal from ethanol, bearing a striking resemblance to human subjective reports (Schulteis and Liu 2006) (Fig. 2). These results demonstrate that the elevation in brain reward thresholds following prolonged access to alcohol may fail to return to baseline levels between repeated and prolonged exposure to alcohol self-administration (i.e., a residual reward deficit), thus creating the greater elevation in reward thresholds observed during withdrawal from chronic ethanol. Rapid acute tolerance and opponent process-like effects in response to the hedonic effects of alcohol have been reported in human studies using the alcohol clamp procedure (Morzorati et al. 2002). These data provide compelling evidence for brain reward dysfunction with chronic alcohol, which provides strong support for a hedonic allostasis model of alcoholism (Koob 2003).
