Diurnal variation in sensory and pain thresholds correlated with mood states.

Twenty-two healthy volunteers were tested for diurnal variations in six mood states and in the sensory and pain thresholds. Cutaneous electrical stimulation was used to detect sensory and pain thresholds and a Mood Questionnaire was used to assess mood states. Both sensory and pain thresholds were found to be significantly lower in the afternoon than in the morning. The detection and pain thresholds were not related to the mood states.