Nocebo and Psychological Factors in Irritable Bowel Syndrome (IBS): A Scoping Review

 There is considerable information about the interrelation of functional gastrointestinal disorders (FGIDs) and psychological disorders, called gut-brain interaction. Physiological and psychological variables have been linked with the etiology and severity of IBS. The nocebo effect (the opposite of placebo) is defined as increase in pain or other symptoms after use of an inactive or inert treatment/agent purported to increase pain or unpleasant symptoms. Some psychological mechanisms of nocebo include expectancies, conditioning, learning, memory, motivation, somatic focus, reward, anxiety, and meaning. Moreover, neurobiological factors are associated with the etiology of this phenomenon. The aim of present study is a discussion of the definition, existence, prevalence, etiology, and characteristics of the nocebo effect in irritable bowel syndrome (IBS).

 This paper presents a scoping review of the existence, frequency, and importance of the nocebo effect in IBS patients. Data sources included PubMed, PsycINFO, Google Scholar, and Scopus which were searched from their inception dates to 2022.

 The review of the obtained articles showed that psychological factors such as depression, anxiety, psychological distress, and some personality traits such as neuroticism are related to the occurrence of nocebo responses in IBS patients.

 The psychological factors associated with nocebo responses include expectancies, conditioning, learning, memory, patient’s personality. Moreover, societal factors and the quality of the patient-physician interaction, and neurobiological factors influence the process of diagnosis, course, and treatment of IBS through nocebo responses. Compared to the extensive research data related to the placebo effect, there is little information and few articles on the role of nocebo, especially in FGIDs. This paper summarizes the scope and importance of the nocebo effect and IBS and its interrelations with psychological factors like personality, anxiety, depression, and psychological distress.