Background: There are a number of psychological mechanisms whose impact on the placebo effect are well supported, such as expectancy and enhanced interaction. There are also cognitive factors, such as cognitive reappraisal, which have been shown to reduce effective impact and could potentially enhance a placebo response. The aim of this study is to examine whether context effects impact stress, more than commercially available treatments such as Bach flower remedies.
Method: This study will use a 2X2 double-blind placebo-controlled randomised trial design to evaluate the effects of Bach Flower solution versus placebo in stress reactivity and recovery and to examine the role of enhanced interaction and cognitive reappraisal (CRA). A group of 100 participants will be randomised to receive Bach flower remedy or Placebo. Within these treatment groups, participants will be further randomised to receive a) Enhanced interaction with placebo and stress CRA, or b) Neutral or limited interaction and CRA. Treatment is 4 drops of solution diluted in water. Participants will then be subjected the Sing-a-song stress test (SSST) post treatment. Heart rate reactivity and recovery will be measured to evaluate physiological stress. Baseline differences will be assessed using the Hospital Anxiety and Depression Scale (HADS) (Zigmond, & Snaith, 1983), the interaction will be assessed using the Consultation and Relational Empathy Questionnaire (CARE, Mercer et al., 2004), and evaluation of treatment beliefs will be done using the Credibility / Expectancy Questionnaire (Devilly & Borkovec, 2000).