The Effects of Moderate Doses of Alcohol on Judgement, Drug Guessing and Subjective Reports of Mood

Abstract

The effects of alcohol ingestion on mood and judgment tasks were investigated in a double-blind study of 48 young, healthy adults who were randomly assigned to one of four treatment conditions, in which they consumed a 500 ml drink containing either 0.25 ml/kg (0.197 g/kg) of alcohol or 0.50 ml/kg (0.394 g/kg) of alcohol, or which contained no alcohol — a control drink or a placebo. Subjects completed several tasks: one prior to consuming the drink and several afterwards. The results showed that the mood and drug guessing tasks were sensitive to the effects of alcohol but the simple judgment task was not. In general, the subjects in the higher alcohol condition reported more negative moods 40 min after the drink than subjects in the other conditions. There was a significant interaction between treatment condition and gender, based on the fact that the male subjects in the higher alcohol condition reported being more drowsy, excited, fuzzy, clumsy, mentally slow and incompetent than the males in the control condition. At the end of the experiment, subjects were asked to guess whether their drink had contained any alcohol; the results showed that more than a quarter of the subjects who received no alcohol thought that there had been alcohol in their drinks. Also, because all the subjects in the higher alcohol condition guessed correctly that there had been alcohol in their drinks, the procedure for masking higher alcohol doses (around 0.50 ml/kg and higher) is questioned.