Circadian Variation of Ethanol Metabolism in Alcoholics*

Summary The rate of ethanol metabolism was determined for 20 alcoholics during afternoon and evening drinking sessions on two consecutive days. Alcoholics demonstrated a faster rate of ethanol metabolism in the evening as compared to the afternoon, suggesting a circadian variation in the rate of ethanol metabolism. Previous drinking on the first day appeared to increase the rate of ethanol metabolism on the second drinking day. This circadian variation of ethanol metabolism, which was present following two weeks of abstinence and one day of heavy drinking, is different from that reported for non‐alcoholics. This suggests that other circadian rhythms may be affected in alcoholics, even after they have been dried out for several weeks. Altered circadian rhythms may partially explain the alcoholics' difficulty in re‐adjusting to social demands.