Effects of emotional context and tactile stimulation on the placebo response in a nausea model

• Applicant: Professorin Dr. Karin Meißner
• Subject Area: Personality Psychology, Clinical and Medical Psychology, Methodology ; Biological Psychiatry
• Term: from 2013 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 138279939

Context factors, such as verbal suggestions of the expected treatment effect, the characteristics of the treatment, or the emotional state of a patient can improve or worsen a symptom or condition – a response which is referred to as ‘placebo response’ (when the outcome is positive), or ‘nocebo response’ (when the outcome is negative). Notably, context factors also influence the effects of medical (e.g., pharmacological) treatments. Besides pain, nausea is one of the few medical conditions for which placebo responses have been confirmed so far in clinical populations. In contrast to placebo pain research, the mechanisms underlying placebo responses on nausea are largely unknown and the number of mechanistic studies in this area of placebo research is low. In this project, we aim to investigate whether the modulation of context factors can maximize and minimize placebo responses on nausea, and which neurobiological systems are involved. In the first experiment, we aim to test the hypothesis that a placebo intervention which includes tactile sensations induces a larger placebo response on nausea than a placebo intervention without such stimulation. In the second experiment we aim to investigate the relationship between experimentally induced negative emotions and the placebo response on nausea. In both experiments the severity of nausea and stress will be assessed not only by symptom ratings but also objectively by autonomic and humoral measurements. Furthermore, we will assess ghrelin in order to test the hypothesis that this hormone plays an important role for the modulation of nausea by placebo interventions. From a clinical point of view, the investigation of placebo responses on nausea is of utmost relevance, given that nausea cannot be controlled sufficiently by pharmacological treatment approaches. The elucidation of psychological factors that modulate nausea during placebo interventions can help to increase the placebo component of given treatments, and thus their total benefit for the patient. The study of placebo responses on nausea is also of interest from a neurobiological point of view, because it will contribute to the ongoing debate of whether placebo interventions improve mainly symptoms, or also affect the functions of peripheral organs.

• DFG Programme: Research Units
• Subproject of: FOR 1328: Expectation and Conditioning as Basic Processes of the Placebo and Nocebo Response
• Participating Person: Professor Dr. Matthias Tschöp