Alcohol and the balanced-placebo design: the role of experimenter demands in expectancy

A new paradigm for credibly administering placebo alcohol to underage drinkers

BACKGROUND

The primary goal of this study was to establish a paradigm for credibly administering placebo alcohol to underage drinkers. We also sought to create a new, valid procedure for establishing placebo alcohol believability.

METHOD

Participants were 138 American college students (66.7% female) predominantly (90.0%) under the legal drinking age. Groups of 2-3 participants and one same-sex confederate consumed mixed drinks, purportedly containing alcohol, ad-lib in a naturalistic bar-laboratory for 20 min. All beverages, however, were non-alcoholic but we used visual, olfactory, and taste cues to maximize placebo credibility. Also, the confederate made two scripted statements designed to increase the perception of drinking real alcohol. After the drinking portion, participants responded to survey items related to alcohol consumption and intoxication. Next, they were individually debriefed, with open-ended responses used to make a determination of whether the participant was deceived with respect to placebo alcohol.

RESULTS

All participants estimated consuming some amount of alcohol. However, using a more conservative criteria for estimating alcohol believability based on the debrief, 89.1% of participants were classified as deceived. Deceived participants were much more likely to estimate having a positive blood alcohol content and to say that their current level of intoxication was typical given the amount of alcohol consumed than non-deceived participants.

DISCUSSION

Credibly administering placebo alcohol to underage drinkers is possible. This approach carries great potential for future laboratory work. In addition, the methodology used here to classify participants as deceived or not deceived appears valid based on self-reported BAC estimation and intoxication levels.

Understanding alcohol expectancy effects: revisiting the placebo condition

This article summarizes a symposium organized and cochaired by Maria Testa and presented at the 2005 Annual Meeting of the Research Society on Alcoholism, in Santa Barbara, California. The symposium explored issues relevant to understanding the function of placebo conditions and to interpreting placebo effects. Cochair Mark Fillmore began with an overview of the use of placebo conditions in alcohol research, focusing on methodological issues. Jeanette Norris and her colleagues conducted a review of studies examining placebo conditions among women. They conclude that expectancy effects are limited to a few domains. Maria Testa and Antonia Abbey presented papers suggesting that placebo manipulations may result in unanticipated compensatory effects in actual or hypothetical social situations. That is, placebo participants may compensate for anticipated cognitive impairment through vigilant attention to situational cues. John Curtin's research suggests that the compensatory strategies of placebo participants appear to involve a sensitization of evaluative control, resulting in improved performance. Kenneth Leonard provided concluding remarks on the meaning of placebo effects and the value of placebo conditions in research.

Implications of placebo theory for clinical research and practice in pain management

We review three possible theoretical mechanisms for the placebo effect: conditioning, expectancy and endogenous opiates and consider the implications of the first two for clinical research and practice in the area of pain management. Methodological issues in the use of placebos as controls are discussed and include subtractive versus additive expectancy effects, no treatment controls, active placebo controls, the balanced placebo design, between- versus within-group designs, triple blind methodology and the double expectancy design. Therapeutically, the possibility of shaping negative placebo responses through placebo sag, overservicing and the use of placebos on their own are explored. Suggestions for using conditioned placebos strategically in conjunction with nonplacebos are made and ways of maximizing the placebo component of nonplacebo treatments are examined. Finally, the importance of investigating the placebo effect in its own right is advocated in order to better understand the long-neglected psychological aspects of the therapeutic transaction.

Selective effects of alcohol on Wisconsin Card Sorting Test performance

Social drinker volunteers were randomly assigned to the four cells of a balanced placebo design, with 10 males and 10 females per cell. They consumed a beverage which contained either tonic water only, or tonic water plus sufficient vodka to induce peak blood alcohol levels of approximately 0.05%. Subjects then completed a computer version of the Wisconsin Card Sorting Test (WCST) in two runs. Compared to tonic only, beverage alcohol selectively increased per cent perseverative errors as well as other measures of perseveration and the number of trials, p less than 0.05. Results are interpreted in terms of an hypothesized differential action on functions of the frontal cortex in addition to possible non-specific effects of alcohol. Issues pertaining to expectancy interpretations are also discussed.