Alcohol and Expectancy: subjective, psychophysiological and behavioral responses to alcohol stimuli in severely, moderately and non-dependent drinkers

Thirty male subjects, 10 severely and 10 moderately alcohol dependent, along with 10 non-dependent controls, were studied in four experimental drinking conditions. Each subject participated in each condition. All subjects received a priming dose of 2 ml 40% vodka/kg or placebo, and a drinking test of 1 ml 40% vodka/kg 45 minutes later. Subjects were told that the priming dose contained ‘alcohol’ in two conditions and ‘soft drinks’ in the two other conditions of the Balanced placebo design. Self-reported desire for a drink and experienced effects from alcohol were more influenced by instructions than by the actual presence of alcohol, although a peak BAG of 0.11% were reached if all available alcohol were consumed (not all subjects did so). Severely dependent subjects demonstrated more craning than the other groups, this difference was observed in the presence of information about alcohol, regardless of whether alcohol was present or not. No differences in speed of drinking were found. The severely dependent subjects showed a higher general arousal than moderately and non-dependent subjects in this experimental setting, as measured by skin conductance level, and they displayed a higher skin conductance response to the instruction that alcohol was to be given. Severely dependent subjects showed a hypothermic response to alcohol. The results confirm our previous findings that expectations of alcohol exerts greater influence on craving than pharmacological effects of alcohol, but the severely dependent subjects are reacting more strongly to alcohol cues than less dependent alcoholics. In addition, the experiment demonstrates that psychophysiological responses are elicited by alcohol cues, and supports a classical conditioning model of alcohol dependence.