[Placebo effects and adverse effects in clinical trials]

Area of Science:

• Clinical pharmacology
• Evidence-based medicine
• Psychosomatic medicine

Context:

• Placebo medications are widely used in clinical trials.
• While placebo effects are well-documented, placebo-induced adverse drug reactions (ADRs) are less understood.
• This study investigates placebo efficacy and tolerability across diverse therapeutic areas.

Purpose:

• To analyze placebo efficacy and tolerability using international clinical data from placebo-controlled studies.
• To compare placebo effects and ADRs across neuropsychiatry, cardiology, metabolism, and gastroenterology indications.
• To determine the significance of placebo effects and ADRs in the context of clinical trial interpretation.

Summary:

• Placebo efficacy varied significantly across indication groups and within them, showing notable effects in mild stroke and angina but not in diabetes.
• Adverse drug reactions (ADRs) were observed under placebo treatment, with frequencies and types mirroring those of active drugs and varying by indication.
• Placebo-induced ADRs, such as dry mouth, were sometimes reported more frequently than with active verum medication.

Impact:

• Placebo therapy is an active intervention, not a 'non-therapy,' demonstrating significant efficacy and potential for ADRs.
• Knowledge of placebo effects and ADRs is essential for accurately judging the efficacy of verum (active) medications in clinical trials.
• Understanding placebo mechanisms is vital, as non-evidence-based use of placebos can be harmful.