Effects of pain and fear stimulus intensity levels on pain responding in chronic pain patients

Fear has been found to increase and decrease pain responding in various contexts, and the effects of fear and pain stimulus intensity levels on pain responding have not been examined. Forty chronic pain patients were exposed to an algometer pressure pain device which stimulated different fingers; there were two levels of pressure pain (i.e., high and low). Also, there were two levels of induced fear (i.e., high and low). Significant main effects of pain stimulus intensity level were found on threshold pain time, tolerance pain time, and self-reports of fear and pain. Also, a significant main effect of gender was found on tolerance pain time. Pain and fear levels interacted for heart rate; significant increases in heart rate occurred only in the combined high pain and high fear condition. Sensitivity to pain stimulus intensity, the effects of stimulus intensity on gender, and the additive effects of high fear and pain are discussed