Anxiety-like behaviors following chronic ethanol exposure

Rodent models of ethanol withdrawal-induced anxiety have been used to explore the neurobiology underlying withdrawal and to evaluate the utility of therapeutic agents aimed at reducing withdrawal severity. Of the many tests of anxiety-like behavior, the elevated plus maze, light/dark box, and open field are the most commonly used. In general, ethanol withdrawal decreases most or all of the individual behaviors recorded in these tasks, indicating the occurrence of an anxiogenic-like effect of withdrawal in rodents, although these effects of withdrawal have not always been found. Potential problems with interpreting the effects of withdrawal as being indicative of an anxiety-like state include the effects of withdrawal on motivation to explore an apparatus, non-specific effects of withdrawal on locomotion, and the use of test parameters that have not been pharmacologically validated. For example, most of the published studies interpreted as having shown increased anxiety-like behavior during ethanol withdrawal have also observed concurrent decreases in locomotion. At a minimum, a given test of anxiety-like behavior during withdrawal should be responsive to the dose and duration of ethanol exposure that was used to produce physical dependence, and should not non-specifically decrease locomotion. In addition, standard anxiolytic drugs should ameliorate the anxiogenic-like effects of withdrawal, preferably in multiple tests of anxiety-like behavior. (C) 2004 Elsevier Ltd. All rights reserved.