Alcohol-induced state-dependent learning: Differentiating stimulus and storage hypotheses

State-dependent effects of alcohol have been demonstrated in animals and man. Most studies have used tasks for which accurate performance typically requires that stimulus input was adequately stored initially and that the items were retrieved at the time of testing. Thus an alcohol-induced decrement in performance could be due to impaired storage, impaired retrieval, or both. The purpose of this experiment was to distinguish between stimulus and storage hypotheses of state-dependent learning (SDL). Sixteen subjects were used in a 2×2 design in which the task involved the learning and recall of a 19-item ‘route’ map. During initial learning, all subjects were sober. Immediately after learning, half the subjects were given a moderate dose of alcohol. Twenty-four hours later, all subjects were tested for recall under the same or different conditions. Greater retention was found for those subjects whose drug states were the same in memory storage/consolidation and retrieval. Thus an alcohol state effective during the memory consolidation interval following acquisition appears to be a sufficient condition for producing SDL. In this context, SDL might be better termed state-dependent memory storage and retrieval. The implications of these results for the aetiology and treatment of alcohol dependence are discussed.