The role of anxiety in negative treatment expectations and its impact on pain perception

This unicentre, randomized, controlled clinical trial following a parallel-group between-subject design aims to systematically investigate the impacts of an anxiety modulation through a single oral dose of midazolam 2mg in pain related and general state anxiety and their effects on treatment expectations and subjective pain hyperalgesia (primary outcome) in healthy volunteers in a nocebo treatment with Cold Pressor Test and a sham naloxone infusion. Secondary outcomes comprise the pharmacokinetics of midazolam (2mg), temporal dynamics of salivary stress markers (salivary alpha amylase and cortisol), measurement of perceived pain related stress as well as pain related and general state anxiety, expectations regarding the treatment as well as tolerability of it and the credibility of the study. To systematically address potential predictors of nocebo hyperalgesia in healthy subjects, psychometric predictors (expectations and previous experiences regarding the exam (Generic rating scale for previous treatment experiences, treatment expectations, and treatment effects - GEEE), somatosensory amplification (Somatosensory Amplification Scale, SSAS), perceived stress (Perceived Stress Scale, PSS), pain related stress, pain related anxiety and state and trait anxiety and depression (Stress Visual Analogue Scale, Anxiety Analogue Scale, State-Trait-Angst-Depressions- Inventar, STADI State), fear of pain (Fear of Pain Questionnaire - III, FPQ-III), catastrophising thinking related to pain (Pain Catastrophizing Scale, PCS), personality factors (10 item Big Five Inventory- BFI-10, Behavioral Inhibition System Behavioral Approach System - BISBAS) are also examined in this study.