Effects of Diazepam on Human Pain Tolerance and Pain Sensitivity

Abstract

Three experiments were carried out to examine the effects of 10 mg of orally administered diazepam on the human pain experience. The first two studies focused on the tolerance of tourniquet pain and the changes in transitory anxiety associated with continuing pain. The third study was concerned with the effect of the drug on the perception of brief and precisely controlled radiant heat pain stimuli. Subjects who ingested diazepam tolerated the presence of the painful tourniquet longer than those who ingested a placebo or aspirin. Diazepam significantly reduced the anxiety associated with the most intense tourniquet pain in contrast to the placebo, but not in contrast to aspirin, but it had no effects on sensory sensitivity to radiant heat pain nor on the willingness of subjects to label noxious experience as pain. The results suggest that the drug affects the emotional-motivational component of the pain experience, but not the sensory-discriminative component or the central control of pain.