| dc.description | Theory and research on the psychological consequences of exposure to aversive events provided the background for this dissertation, which predicted that providing information about an impending aversive event would influence predictions about and responses to pain. This dissertation investigated: the effects of stimulus predictability on pain prediction, perception and pain behaviour; whether these effects remained constant across pain from different sources; and the relationship between perceived control, pain perception and pain behaviour. Twenty chronic low back pain patients and 20 matched, pain-free controls participated in a series of experiments which examined these effects. Baseline, between group differences were established in anxiety, depression, pain behaviour, handicap and perceived control over pain. In Experiment 2, in which cold pressor pain was used, there were no differences between groups in pain predictions, in patterns of predicting pain during repeated exposures to a painful stimulus, or in pain thresholds, even after repeated exposure. Experiment 3 confirmed, under longer exposure durations, that there were no differences between groups in pain predictions. Pain patients displayed an increased sensitivity to pain under conditions of low predictability. Both groups predicted significantly more pain and displayed significantly lower pain thresholds under conditions of low versus high stimulus predictability. Experiments 4 and 5 produced similar effects and demonstrated generalization of these findings to different, more clinically relevant, pain stimuli. Pain patients displayed more pain behaviour than did control subjects in all experiments. Neither group's displays of pain behaviour were affected by variations in stimulus predictability. Relations were found, for both groups, between perceived control over pain, pain predictions and pain thresholds but not between perceived control and pain reports or behaviour during acute pain stimulation. There were significant correlations between pain patients' perceptions of pain and their displays of pain behaviour during cold water immersion, but not during step climbing or standing. An argument is presented to suggest that the maintenance of pain and pain behaviour in chronic pain may be better explained by psychosocial and learning theories rather than constitutional theories. | en_US |
