Chronic low back pain: predictions of pain and relationship to anxiety and avoidance

The present study examined the discrepancy between prediction and experience of pain in 20 chronic low back pain (CLBP) patients undertaking a series of standard physical exercises. Subjects gave ratings of predicted pain and anxiety before each exercise and a rating of the pain experienced during the exercise. Contrary to prediction, the majority of CLBP patients predicted less pain than they subsequently experienced. Moreover, multiple regression analysis showed that, in these patients, the greater the discrepancy between predicted and experienced pain the greater the increase in pain predicted for the subsequent exercise. Anxiety was greater the higher the level of pain predicted, although it was not significantly related to the amount of pain experienced on the previous exercise or to the discrepancy between predicted and experienced pain. However, the discrepancy between predicted and experienced pain was found to be related to subsequent physical performance whereas the other variables were not; the more that pain exceeded expectations on the first exercise the less patients performed on the subsequent exercises. The results of this study are compared with those of previous studies and the implications of the findings to the maintenance of CLBP are discussed.