A placebo is an inert substance normally used in clinical trials for comparison with an active substance. However, a placebo has been shown to have an effect on its own; commonly known as the placebo effect. A placebo is an essential component in the design of conclusive clinical trials but has itself become the focus of intense research. The placebo effect is partly the result of positive expectations of the recipient on the state of health. Conversely, a nocebo effect is when negative expectations from a substance lead to poor treatment outcomes and/or adverse events. Randomized controlled trials in functional urology have demonstrated the importance of the placebo and nocebo effects across different diseases such as overactive bladder, urinary incontinence, lower urinary tract symptoms and interstitial cystitis/painful bladder syndrome, as well as male and female sexual dysfunction. Understanding the true nature of the placebo-nocebo complex and the scope of its effect in functional urology could help urologists to maximize the positive effects of this phenomenon while minimizing its potentially negative effects.

Department of Urology 2nd Faculty of Medicine Charles University Prague Czech Republic

Department of Urology Comprehensive Cancer Center Medical University of Vienna Vienna Austria

Department of Urology The Jikei University School of Medicine Tokyo Japan

Department of Urology University Medical Center Hamburg Eppendorf Hamburg Germany

Department of Urology University of Texas Southwestern Medical Center Dallas TX USA

Department of Urology Weill Cornell Medical College New York NY USA

European Association of Urology research foundation Arnhem Netherlands

Hourani Center for Applied Scientific Research Al Ahliyya Amman University Amman Jordan

Institute for Urology and Reproductive Health Sechenov University Moscow Russia

Karl Landsteiner Institute of Urology and Andrology Vienna Austria

King Fahad Specialist Hospital Dammam Dammam Saudi Arabia

King Faisal Medical City Abha Saudi Arabia

Men's Health and Reproductive Health Research Center Shahid Beheshti University of Medical Sciences Tehran Iran

Research Center for Evidence Based Medicine Tabriz University of Medical Sciences Tabriz Iran

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