Over the past decades interpersonal trust has become a prominent subject in medical and psychotherapy research. Although the fundamental role and importance of trust in the clinical encounter as well as for the clinical outcome has been highlighted and extensively described, the role of a trustful patient-provider relationship in the treatment process remains vague and consensus on generally valid factors and mechanisms underlying the trust-health association is still lacking. With regard to current medical research, unconscious factors and processes seem to play significant role in the treatment effectivity. In this context, trust represents a promising candidate factor. Interestingly, the concept of interpersonal trust has also received ample attention from placebo research and shifted the idea of an inert placebo agent toward the concept of an implicit and explicit stimulation, driven by the psychosocial context it is embedded in. Therefore, the planned project will help to elucidate the impact of a trustful relationship on the general health outcome as well as its role in the expectation-mediated placebo analgesia response, thereby investigating the influence of an explicit and implicit trust induction.
Because the dissertation aims to grasp and operationalize the multifactorial concept of trust and its interdisciplinary facets, a systematic review and two experiments with healthy participants will be conducted. Whereas a systematic review of articles investigating the association between a trustful patient-provider relationship and the clinical outcome constitutes a first estimate and theoretical basis of trust effects, two experimental paradigms will implicitly as well as explicitly manipulate and assess the interpersonal trust, illuminating the concept of interpersonal trust from an empirical point of view. In both double-blind experiments right-handed healthy males will be either suggested an analgesia or neutral expectation. Furthermore, half of the participants will be allocated to the trust condition, implying a trustful participant-investigator-relationship in experiment 1 and an implicit trust priming in experiment 2. As dependent variables, heat pain threshold, tolerance, skin conductance, Salivary Alpha-Amylase (sAA) as objective data as well as subjective data (Visual analogue scale (VAS), questionnaire) will be collected.
Given the significant role of interpersonal trust on clinical outcome, the expected insight in these aspects of treatment effects are scientifically and clinically important for the understanding and the enhancement of clinical interventions.