Ph.D Thesis

Ph.D StudentPud Dorit
SubjectThe Relationship between Sensitivity to Pain and
Responsiveness to Analgesics to Personality
DepartmentDepartment of Medicine
Supervisors PROF. David Yarnitsky
PROF. Elon Eisnberg


The aim of the present study was to examine the possible role of personality traits in the interpersonal variability of sensitivity to pain and responsiveness to analgesics. More specifically, it was intended to test whether the three personality dimensions, based on neurochemical transmitters [harm avoidance (HA)- serotonin; reward dependence (RD)- noradrenaline; and novelty seeking (NS) - dopamine], as suggested by Cloninger, can predict interpersonal differences in sensitivity to pain. Methods: Ninety-four healthy volunteers were exposed to cold (CPT) and hot (TSA) pain stimuli; psychophysical dimensions of pain response were measured (pain threshold, tolerance, and intensity), as well as autonomic variables (blood pressure and heart rate) before and during the stimuli. Assessments of anxiety level and personality traits were obtained through the Tridimensional Personality Questionnaire. Results: No differences between men and women were found in pain parameters. Regression analysis showed a high correlation between HA scores and VAS. When subjects were categorized into four groups: 1) High HA/High RD; 2) High HA/Low RD; 3) Low HA/High RD; and 4) Low HA/Low RD, Group 4 demonstrated the lowest, whereas group 2 showed the highest sensitivity to pain. The other two groups were in-between. State anxiety was positively correlated to both HA and sensitivity to cold pain.  Autonomic activity increased during pain stimulation. Baseline blood pressure was negatively correlated with cold pain responders.  Women were more responsive than men to morphine, as were individuals with a high score of HA. Those with a high score of NS responded more readily to placebo. Conclusions: The findings of the present study show that personality traits can predict sensitivity to pain.