Related Experiment Video
Updated: Jun 25, 2026
05:40
The Motivation for Alcohol Reward: Predictors of Progressive-Ratio Intravenous Alcohol Self-Administration in Humans
Published on: April 28, 2022
Expectancy in double-blind placebo-controlled trials: an example from alcohol dependence
Ben Colagiuri1, Kirsten Morley, Robert Boakes
1School of Psychology, University of Sydney, Sydney, NSW 2006, Australia. benc@psych.usyd.edu.au
Psychotherapy and Psychosomatics
|March 10, 2009
Summary
Patients believing they received active medication in a clinical trial reported better outcomes for alcohol dependence, regardless of actual treatment. This highlights the impact of patient expectancy on trial results.
Area of Science:
- Clinical Psychology
- Psychopharmacology
- Medical Research Methodology
Background:
- Double-blind placebo-controlled trials aim to mitigate expectancy effects on study outcomes.
- The consistent effectiveness of these trials in controlling for expectancy is debated.
Purpose of the Study:
- To investigate the influence of patient expectancy on outcomes in a clinical trial for alcohol dependence.
- To examine whether perceived medication assignment impacts treatment effectiveness.
Main Methods:
- Reanalysis of a 12-week clinical trial involving 169 alcohol-dependent patients.
- Patients received naltrexone, acamprosate, or placebo.
- Participants reported their belief about receiving active medication versus placebo, alongside standard outcome assessments.
Main Results:
- No significant differences in outcomes were observed between the actual treatment groups.
- Patients who believed they received active medication showed reduced alcohol consumption, dependence symptoms, and cravings.
- Perceived medication allocation was a significant predictor of health outcomes, independent of the actual treatment received.
Conclusions:
- Patient expectancy significantly influences outcomes in clinical trials for alcohol dependence.
- Discrepancies between clinical trial administration and standard medical practice, particularly regarding expectancy, may affect trial validity.
- Findings underscore the importance of considering psychological factors in treatment efficacy research.
More Related Videos
13:24A Procedure to Observe Context-induced Renewal of Pavlovian-conditioned Alcohol-seeking Behavior in Rats
Published on: September 19, 2014
07:50A Method for Evaluating the Reinforcing Properties of Ethanol in Rats without Water Deprivation, Saccharin Fading or Extended Access Training
Published on: January 29, 2017
Related Concept Videos
02:07Blind Procedures
Ideally, the people who observe and record the children’s behavior are unaware of who was assigned to the experimental or control group, in order to control for experimenter bias. Experimenter bias refers to the possibility that a researcher’s expectations might skew the results of the study. Remember, conducting an experiment requires a lot of planning, and the people involved in the research project have a vested interest in supporting their hypotheses. If the observers knew which child was...
01:54The Placebo Effect
The placebo effect occurs when people's expectations or beliefs influence or determine their experience in a given situation. In other words, simply expecting something to happen can actually make it happen.
01:11Blinding
Blinding is a commonly used method of not telling participants which treatment a subject is receiving. Blinding is a critical part of a randomized control trial or RCT. It reduces the bias that affects the results. In an RCT, blinding is used in the form of a placebo. A placebo effect occurs when untreated subjects falsely believe they have received the treatment and report improved symptoms. A placebo or a dummy treatment is administered to subjects to negate the bias caused by such an effect.
01:15Drug Abuse and Addiction: Pharmacological Phenomena
Drug dependence, abuse, and addiction are complex phenomena that can precipitate various abnormal states. Physical dependence refers to a state of pharmacological adaptation to a drug. This adaptation often results in tolerance—a reduced response to the drug after repeated administrations. When the drug use is abruptly stopped, withdrawal symptoms occur due to the body's need to readjust from the pharmacologically induced imbalance. However, tolerance and withdrawal symptoms do not necessarily...
01:17Drug Dependence
Medications are typically administered to achieve therapeutic effects. Some drugs can modify an individual's mood and perception, frequently resulting in various enjoyable experiences. However, this can result in drug dependency, a condition marked by continuous drug use despite potential negative consequences. Drug dependency primarily falls into two categories: psychological and physical dependence. Psychological dependence occurs when the pleasurable feelings induced by the drug...
01:27CNS Depressants: Alcohol and Nicotine
Ethanol, a clear colorless alcohol, has been consumed by humans for millennia, but its effects on the body are far from benign. At lower doses, it induces decreased inhibitions and loquaciousness, leading to its social appeal. However, it can cause severe consequences at higher doses, such as coma and respiratory depression, due to its zero-order elimination kinetics. Chronic ethanol abuse wreaks havoc on multiple organ systems, particularly the CNS and the liver. Abrupt cessation of ethanol...