Potentiation of ethanol withdrawal by prior dependence.

Thirty rats were randomly assigned to three groups. Group 1 was given a 21-day exposure to an ethanol (EtOH) liquid diet, while Groups 2 and 3 were given equivalent amounts of an isocaloric non-EtOH liquid diet. Group 1 rats had withdrawal syndromes following EtOH removal. After a two-week recovery period, Groups 1 and 2 were both exposed to an EtOH diet, while Group 3 again received an isocaloric non-EtOH liquid diet. Groups 1 and 2 were withdrawn after 12 days of EtOH exposure and were rated with a behavioral withdrawal rating scale, for which interobserver reliability estimates were determined. Previously dependent (Group 1) rats showed more severe withdrawal syndromes, including a higher incidence of seizures, than rats undergoing their initial withdrawal (Group 2). Studies that do not agree with this finding are discussed.