Fig. 2

Personality traits and psychological factors were strongly linked to the magnitude of response. a The covariance matrix shows the relationship between each subscale in the questionnaire data described in detail in Supplementary Table 4. b Univariate statistics showed no group differences surviving Bonferroni correction for 37 comparisons. c However, openness (from the big 5 personality dimensions) and 4 out of 8 subscales from the Multidimensional Assessment of Interoceptive Awareness (MAIA)- Not Distracting (maia/nd), Attention Regulation (maia/a), Emotional Awareness (maia/e), and Self-Regulation (maia/sr)- correlated with the magnitude of response after correcting for multiple comparisons (p < 0.0013; shown in black). Patients with increased emotional awareness experience greater placebo analgesia (Maia/e displayed in d), whereas patients who tend not to ignore or distract themselves from discomfort experience less placebo analgesia (Mais/nd displayed in e). The red circle marks an outlier on the magnitude of response that was excluded. Other abbreviations used: Pain Anxiety Symptoms Scale (PASS) and its 4 subscales—Avoidance (pass/a), Cognitive (pass/c), Fear (pass/f), and Physiological (pass/p); Pain Catastrophizing Scale (PCS) and its 3 subscales—Rumination (pcs/r), Magnification (pcs/m), and Helplessness (pcs/h); Chronic Pain Acceptance Questionnaire (CPAQ) and its 2 subscores—Activity Engagement (cpaq/a) and Pain Willingness (cpaq/pw); the remaining 4 MAIA subscales—Noticing (maia/n); Not Worrying (maia/nw); Body Listening (maia/bl); and Trusting (maia/t); Pain Sensitivity Questionnaire (PSQ) and its 2 subscales—Painful (psq/p) and Non-Painful (psq/np); Positive and Negative Affect Scale (PANAS) with Positive (panas/p) and Negative (panas/n) subscales; Five Facets of Mindfulness (FFM) with its 5 subscales—Observe (ffm/o), Describe (ffm/d), Act with Awareness (ffm/a), Non-Judge (ffm/nj), and Non-React (ffm/nr); Emotional Regulation Questionnaire with its Reappraisal (erq/r) and Suppression (erq/s) subscales; Attentional Control Scale (acs); Emotional Attentional Control Scale (eacs); Life Orientation Test—Revised version (lotr); Loss Aversion Questionnaire (laq); and Beck Depression Index (bdi)