An evaluation of the balanced placebo design in alcohol administration research.

Abstract

Results from a study using the balanced placebo design to assess alcohol's effects on anxiety raise serious doubts about the utility of the design even at moderate blood alcohol concentrations. Despite being informed that they were not drinking alcohol, 44% of the subjects who were administered alcohol reported consuming at least some alcohol. Moreover, subjects' scores on the Marlowe-Crowne Social Desirability Index (MCSD) were associated with deception success, suggesting that individual differences in reporting bias influence the manipulation. In contrast, only 6% of subjects who were told that they had consumed alcohol but were given tonic water were not deceived. Among subjects in this placebo condition, scores on the MCSD were not associated with success of the deception. These data suggest that at a moderate dose of alcohol, drink deception in the antiplacebo condition is much more difficult to execute than in the placebo condition, and that deception in the former condition may be confounded with experimenter demand.