Performance impairment and increased anxiety resulting from the combination of alcohol and lorazepam.

The interaction between lorazepam (1.0 mg) and low doses of alcohol (1/6 or 1/2 gill of vodka, equal to 6.5 or 19.6 g, respectively) was investigated in a variety of performance tests using a double-blind crossover design. The effects on mood ratings and bodily symptoms were also studied. The subjects were normal student volunteers. Lorazepam significantly impaired performance in a digit symbol substitution test and in number and verbal learning tasks. In the latter, long term recall was also impaired. Alcohol increased subjects' simple reaction time. Self-ratings of sedation were significantly increased by both lorazepam and alcohol alone, and these sedative effects were additive when the drugs were combined. Both lorazepam and alcohol had anxiolytic effects when taken alone, but when combined they made subjects more anxious than they were on placebo. This anxiogenic action of the drug combination was found on two occasions under test conditions where significantly different levels of state-anxiety were observed. These results suggest that benzodiazepine treatment should not be combined with even small quantities of alcohol because of the risk of both psychomotor impairment and possible anxiogenic effects.