Factors that Contribute to Susceptibility of the Placebo/Nocebo Effect in Experimentally Induced Ischemic Arm Pain

Placebo’s (positive expectancies producing positive outcomes) and nocebo’s (negative expectancies producing negative outcomes) are real and measurable effects. Real as these effects may be, predicting individuals that may be susceptible to placebo/nocebo effects has been inconsistent. The present study examined whether measures designed to assess somatization (MSPQ), catastrophizing (PCS) and childhood trauma (CTQ) would predict placebo and nocebo membership. In addition, measures designed to assess anxiety (ASI) anxiety about pain (PASS) and depression (BDI) were evaluated to determine whether anxiety or depression mediates responsiveness. The Hargreaves Thermal Withdrawal test and the submaximal effort tourniquet technique were employed as pain vehicles for the measurement of group differences. No significant effects of planned analyses were observed. However, unplanned analyses of childhood trauma subscales indicated that physical and emotional abuse predicted placebo response. Additionally, emotional neglect trended toward predicting nocebo responsiveness. These results indicate that further studies, correcting for weaknesses, is warranted