Approach and avoidance personality traits in acute pain and placebo analgesia

A matter of personality and point of view: How the interplay of reinforcement sensitivity and general attitudes towards pain impacts the responsivity to acute pain

BACKGROUND

The relatively stable individual differences reflected in Grey's revised reinforcement sensitivity theory (rRST), with foundations in neurophysiology and learning theory, appear particularly applicable to the study of pain. However, remarkably little research has been conducted in this area. In acute pain, activation of the behavioural approach system (BAS), the behavioural inhibition system (BIS) and the fight, flight, freezing system might depend on an individual's evaluation of pain. It was thus hypothesised that higher-order interactions of rRST traits and pain attitudes affect pain responsiveness.

METHODS

To investigate relationships between rRST traits and pain attitudes and to identify patterns between clusters of participants, we conducted a study in which N = 275 healthy participants filled in Reuter and Montag's rRST-Q and the General Attitudes Towards Pain Inventory (GATPI). Experimental (pressure, electrical, thermal) and self-report data of pain responsiveness were collected in a subsample (N = 113).

RESULTS

We found significant correlations between rRST-Q and GATPI subscales of up to r = 0.34. Two clusters were identified, significantly differing in rRST-Q and GATPI scores. Pain avoiders, characterized by high BIS, flight, freezing and negative pain attitudes, were found to be significantly more pain sensitive than pain approachers, characterized by high BAS, fight and positive pain attitudes. Moderate effects (d = 0.56 to d = 0.70) were demonstrated in subjective and objective measures and across pain modalities.

CONCLUSIONS

The present study expands the scientific knowledge on factors influencing pain responsiveness. Future research is needed to confirm implications for chronic pain prevention and therapy, particularly concerning pain avoiders.

SIGNIFICANCE

We have identified two clusters of participants, pain avoiders and pain approachers, that not only present differential patterns of revised reinforcement theory traits and general attitudes towards pain but also differ in their pain responsiveness. Pain avoiders appeared more pain sensitive compared to pain approachers, both in objective and subjective measurements, with implications for the improvement of chronic pain prevention and therapy.

ERP Indicators of Self-Pain and Other Pain Reductions due to Placebo Analgesia Responding: The Moderating Role of the Fight-Flight-Freeze System

This study evaluates the modulation of phasic pain and empathy for pain induced by placebo analgesia during pain and empathy for pain tasks. Because pain can be conceptualized as a dangerous stimulus that generates avoidance, we evaluated how approach and avoidance personality traits modulate pain and empathy for pain responses. We induced placebo analgesia to test whether this also reduces self-pain and other pain. Amplitude measures of the N1, P2, and P3 ERPs components, elicited by electric stimulations, were obtained during a painful control, as well as during a placebo treatment expected to induce placebo analgesia. The placebo treatment produced a reduction in pain and unpleasantness perceived, whereas we observed a decrease in the empathy unpleasantness alone during the empathy pain condition. The moderator effects of the fight-flight-freeze system (FFFS) in the relationships linking P2 and P3 amplitude changes with pain reduction were both significant among low to moderate FFFS values. These observations are consistent with the idea that lower FFFS (active avoidance) scores can predict placebo-induced pain reduction. Finally, in line with the revised Reinforcement Sensitivity Theory (r-RST), we can assume that phasic pain is an aversive stimulus activating the active-avoidance behavior to bring the system back to homeostasis.