Contextual factors in treatment : a meta-analytic and an experimental approach

Context factors have been hypothesized as being a core element in the medical treatment of the patient. Although their importance has extensively been described with regard to the medical and psychotherapeutic treatment, the empirical evidence of two factors, trust in the provider and meaning transformation in a treatment, remains vague. In order to study these two factors we used a two-folded approach: 1) A meta-analysis, quantifying the impact of trust on the health outcome and 2) the development of two experimental paradigms in order to provide a tool to systematically manipulate trust in provider and meaning transformation in order to test for their influence in research and clinical practice.
To quantify the impact of interpersonal trust in the clinical setting a meta-analysis was undertaken. Therefore, 5667 studies were screened. An overall mean effect as well as effect sizes for different subtypes of health outcomes were calculated. Patients reported higher treatment satisfaction, more beneficial health behaviors, less symptoms and a higher quality of life if they trusted their health care professional. With regard to objective health outcomes no direct link to trust was detectable with trust.
In a second step we tested the validity and feasibility of two placebo designs in order to study context factors in an empirical design. First, the effect of opposing therapy rationales was tested, using an open/hidden administration of an expressive writing intervention. The linguistic content analysis indicated plausibiliy of the experimental manipulation for the participants. Moreover, participants in the openly administered condition benefited from the expressive writing intervention in the long-run.
In the second experiment, we tested if the trust game, often used in economic psychology, might be a tool to induce trust for medical research. Therefore we used two fixed trust conditions. Randomly, half of the participants were allocated to the trust condition, implying a trustful participant-investigator-relationship, while the other half was distributed to a non-trustful condition. We found that trust could systematically be manipulated, even controlling for emotions as anger or anxiety. The subjective rating of trust differed from the behavioral response of the participant.
Overall, these three papers try to contribute to a developing research on context factors. Mainly, I want to shed attention on two factors: trust in the provider and meaning transformation, which are less understood and tested in research. Rather than providing a theoretical debate on this topic, this dissertation aims to give an empirical insight and suggests two paradigms to elaborate research on this field. To quantify the mostly untested effects on trust and meaning transformation might be particular important in regard to a cost-benefit oriented health care policy.