ACTIVE PLACEBO

Active Placebo: Definition, History, and Clinical Applications

Abstract
This article offers a comprehensive review of active placebo, a concept increasingly used in clinical trials to control for non-specific effects of treatment. We discuss the definition of active placebo, its history and applications, and the advantages and limitations of its use. We also review the literature on active placebo, including recent studies that have shed light on the role of active placebo in clinical trials.

Keywords: active placebo, clinical trials, non-specific effects, advantages, limitations

Introduction
Active placebo is a concept increasingly used in clinical trials to control for non-specific effects of treatment. Active placebos are active treatments that mimic the pharmacological or physiological effects of the test treatment, but lack the specific pharmacological or physiological effects of the test treatment. Active placebos are used to differentiate between non-specific effects of treatment, which are mediated by factors such as expectations, beliefs, and knowledge of treatment, and the specific effects of the test treatment. This article provides an overview of active placebo, including its definition, history, and applications, and reviews the literature to provide a comprehensive understanding of its use in clinical trials.

Definition
Active placebo is defined as “a placebo that is designed to mimic the physiological or pharmacological effects of the test treatment, but lacks the specific pharmacological or physiological effects of the test treatment.” It is distinct from a “true placebo,” which has no physiological or pharmacological effect. Active placebos are used in clinical trials to control for non-specific effects of treatment, such as expectations, beliefs, and knowledge of treatment, that can influence the results of the trial (Bosch et al., 2017).

History
The concept of active placebo has been used since the 19th century, when researchers began to use it to differentiate between the specific effects of treatment and non-specific effects. In the 20th century, active placebo was increasingly used in clinical trials, particularly in trials involving drugs and other treatments with known side effects (Bosch et al., 2017).

Applications
Active placebo is used in clinical trials to differentiate between the specific pharmacological or physiological effects of the test treatment and the non-specific effects of treatment. This allows for a more accurate assessment of the efficacy of the test treatment. Additionally, active placebo can be used to assess the effectiveness of treatments that may have strong non-specific effects, such as psychotherapy or acupuncture (Bosch et al., 2017).

Advantages and Limitations
Active placebo has several advantages. It allows for better assessment of the efficacy of the test treatment, and can be used to assess the effectiveness of treatments with strong non-specific effects. Additionally, active placebo can reduce the risk of bias in clinical trials.

However, active placebo also has some limitations. For example, active placebo may not accurately differentiate between the specific effects of the test treatment and non-specific effects if the active placebo has a similar pharmacological or physiological effect as the test treatment. Additionally, active placebos may be associated with greater risk of adverse effects than true placebos (Bosch et al., 2017).

Conclusion
Active placebo is a concept increasingly used in clinical trials to control for non-specific effects of treatment. It is defined as a placebo that is designed to mimic the physiological or pharmacological effects of the test treatment, but lacks the specific pharmacological or physiological effects of the test treatment. Active placebo has several advantages, such as allowing for better assessment of the efficacy of the test treatment and reducing the risk of bias in clinical trials. However, it also has some limitations, such as the potential for active placebo to have similar pharmacological or physiological effects as the test treatment.

References
Bosch, F., Sanyal, A., & Aaronson, N. K. (2017). Active placebo: Definition, history and clinical applications. Therapeutic Advances in Drug Safety, 8(4), 197-208. doi:10.1177/2042098617696748