Chronic alcohol neuroadaptation and stress contribute to susceptibility for alcohol craving and relapse

Alcoholism is a chronic relapsing disorder. Major characteristics observed in alcoholics during an initial period of alcohol abstinence are altered physiological functions and a negative emotional state. Evidence suggests that a persistent, cumulative adaptation involving a kindling/allostasis-like process occurs during the course of repeated chronic alcohol exposures that is critical for the negative symptoms observed during alcohol withdrawal. Basic studies have provided evidence for specific neurotransmitters within identified brain sites being responsible for the negative emotion induced by the persistent cumulative adaptation following intermittent-alcohol exposures. After an extended period of abstinence, the cumulative alcohol adaptation increases susceptibility to stress- and alcohol cue-induced negative symptoms and alcohol seeking, both of which can facilitate excessive ingestion of alcohol. In the alcoholic, stressful imagery and alcohol cues alter physiological responses, enhance negative emotion, and induce craving. Brain fMRI imaging following stress and alcohol cues has documented neural changes in specific brain regions of alcoholics not observed in social drinkers. Such altered activity in brain of abstinent alcoholics to stress and alcohol cues is consistent with a continuing ethanol adaptation being responsible. Therapies in alcoholics found to block responses to stress and alcohol cues would presumably be potential treatments by which susceptibility for continued alcohol abuse can be reduced. By continuing to define the neurobiological basis of the sustained alcohol adaptation critical for the increased susceptibility of alcoholics to stress and alcohol cues that facilitate craving, a new era is expected to evolve in which the high rate of relapse in alcoholism is minimized. (C) 2010 Elsevier Inc. All rights reserved.