Reduced level of anxiety in adult Lewis rats after chronic ethanol consumption.

Many studies have shown that chronic ethanol consumption leads to a decline in learning and memory performance in rats and mice. However, other aspects of behavior have received less attention. Anxiety, for example, is known to be affected in alcoholics but has not been studied in animal models of ethanol consumption. In order to study the effects of chronic ethanol consumption on anxiety, twelve 3-month-old Lewis rats were given a 20% ethanol solution for 6 months as the only source of liquid, while a control group (n = 11) received tap water. Both groups were subjected to three different tests three weeks after cessation of treatment. Data analysis indicated that in all three tests the level of anxiety was reduced in the chronic ethanol-treated rats. Therefore, learning and memory measures, especially in aversively motivated tasks, may be confounded by differences in levels of anxiety between control and ethanol-treated rats.