The Influence of Doctor-patient Communication on Treatment Expectation, Placebo and Nocebo Response

The purpose of this study is to determine whether a patient-centered compared to doctor-centered communication style of a physician influences the treatment expectation and the placebo and nocebo response in healthy individuals.

Doctor-patient communication is crucial for the success of treatment and patients´ quality of life. It could be shown that the medical communication style during the consultation has an effect on the treatment expectation and can therefore positively influence the effect of a sham treatment (placebo ointment). The doctor's communication style has already been successfully manipulated in experimental designs. However, the question remains to what extent the doctor's communication style is related to the placebo/nocebo response and the change in effect-related expectations after a one-week intake of a supposedly medical herbal product (drug-free placebo).

It is expected that the patient-centered communication style of the physician has a positive impact on the reduction of stress (placebo response) and the effect-related cognitive expectations. Furthermore, the physician-centered communication style is expected to negatively impact potential side effects (nocebo response) and impact-related expectations.

Participants will be recruited via posters on public notice boards and e-mail distribution lists. After individuals register for participating in the study, they are called by a study assistant. Eligibility criteria are checked and participants are asked questions about control variables (sociodemographic data (age, sex, profession) and symptom report (Generic Assessment of Side Effects GASE)). The subjects are told that an herbal medical product (drug-free placebo pill) is tested for the reduction of stress symptoms (cover story). Subjects are randomly assigned to 3 groups (2 experimental groups: patient-centered communication style, doctor-centered communication style, control treatment: information letter). Eligible participants come in the lab for an experimental appointment. They first complete a questionnaire at baseline assessment about control variables (further sociodemographic data, disability of stress symptoms, anxiety (trait), negative and positive affectivity, communication preferences, beliefs about medicines, adherence) and outcome variables (treatment expectation, placebo response, Nocebo response, blood pressure and heart rate).

Participants in the experimental groups are then informed by a simulated doctor (played by a study assistant) about indications and side effects of the herbal medical product. The doctor applies either a patient-centered or doctor-centered communication style. The patient-centered style is characterized by features such as empathetic communication, open questions, and uses an easily understandable language. The doctor-centered style is defined by an authoritarian and goal-oriented communication. The doctor uses medical terms instead of lay language. In the control treatment participants receive all information about the herbal medical product in an information letter but have no contacted with the simulated doctor. Participating subjects, who receive a medical consultation, complete a brief questionnaire after doctor's consultation about the satisfaction with the consultation and the anticipated treatment expectancy (post-consultation). Then participants in all three groups are asked to take the herbal medical product (placebo pill). At the end of the experimental appointment, participants are asked to complete another questionnaire about the outcome variables (treatment expectation, placebo response, Nocebo response, blood pressure and heart rate) (post-intake). Participating subjects are instructed to take the placebo pill once a day over the next week. Seven days after the first appointment participants are invited to come to the lab for a follow-up assessment (1-week follow-up).

The treatment expectancy is operationalized with visual analogue scale about participant's treatment outcome expectations (VAS, see primary outcomes) at post-intake and 1-week follow-up. The placebo effect is operationalized with visual analogue scale about the relaxation level (VAS, see secondary outcomes) at post-intake and 1-week follow-up.

The nocebo effect is operationalized with the number of symptoms and symptom severity (Generic Assessment of Side Effects GASE, see secondary outcomes) attributed by participants to a medication side effect at post-intake and 1-week follow-up.

Eligibility Criteria:
Inclusion Criteria:

* female
* between 18 and 35 years
* healthy
* adequate ability to see
* fluent in German (reading and writing)

Exclusion Criteria:

* regular intake of medication that enhances relaxation
* intake of psychotropic drugs
* during the past 2 years in psychotherapeutic treatment for diagnosed mental disorder
* current pregnancy or lactation
* students enrolled in medicine, psychology or pharmacy