The moderating effects of tension-reduction alcohol outcome expectancies on placebo responding in individuals with social phobia.

We conjectured that individual differences in tension-reduction alcohol outcome expectancies (TR-AOEs) could produce widely varying responses to manipulations in alcohol-placebo studies and tested this idea by having individuals with social phobia give speeches in front of a group. One speech occurred before and one after participants consumed either a placebo beverage or a control beverage (i.e., a nonalcoholic drink described as containing no alcohol). Study results indicate that the placebo manipulation reduced cognitive and affective symptoms of anxiety to a greater extent for males with high TR-AOEs than for males with low TR-AOEs. This pattern was not found for women in the placebo group or for individuals in the control group. These findings demonstrate a moderating effect of TR-AOEs on the association between the consumption of a placebo beverage and response to an anxiety challenge and highlight the importance of accounting for gender and outcome expectancies when evaluating psychoactive substances.