Anger Inhibition and Pain Modulation

Abstract

Background: The tendency to inhibit anger (anger-in) is associated with increased pain. This relationship may be explained by the negative affectivity hypothesis (anger-in increases negative affect that increases pain). Alternatively, it may be explained by the cognitive resource hypothesis (inhibiting anger limits attentional resources for pain modulation).

Methods: A well-validated picture-viewing paradigm was used in 98 healthy, pain-free individuals who were low or high on anger-in to study the effects of anger-in on emotional modulation of pain and attentional modulation of pain. Painful electrocutaneous stimulations were delivered during and in between pictures to evoke pain and the nociceptive flexion reflex (NFR; a physiological correlate of spinal nociception). Subjective and physiological measures of valence (ratings, facial/corrugator electromyogram) and arousal (ratings, skin conductance) were used to assess reactivity to pictures and emotional inhibition in the high anger-in group.

Results: The high anger-in group reported less unpleasantness, showed less facial displays of negative affect in response to unpleasant pictures, and reported greater arousal to the pleasant pictures. Despite this, both groups experienced similar emotional modulation of pain/NFR. By contrast, the high anger-in group did not show attentional modulation of pain.

Conclusions: These findings support the cognitive resource hypothesis and suggest that overuse of emotional inhibition in high anger-in individuals could contribute to cognitive resource deficits that in turn contribute to pain risk. Moreover, anger-in likely influenced pain processing predominantly via supraspinal (e.g., cortico-cortical) mechanisms because only pain, but not NFR, was associated with anger-in.

Keywords: Attention; Emotion inhibition; Emotion regulation; Pain; Pain risk.

Fig. 1.

Experimental procedures for emotional control of nociception (ECON) testing day. NFR = nociceptive flexion reflex. ERP = event-related potential.

Fig. 2.

Valence (top left graph), arousal (top right graph), corrugator electromyogram (EMG, bottom left graph), and skin conductance (bottom right graph) responses to pictures by picture content (mutilation, neutral, erotica) and anger-in group (high anger-in, low anger-in). Valence ratings scale from 1 (unpleasant) to 9 (pleasant). Arousal ratings scale from 1 (calm) to 9 (excited). In general, mutilation pictures were rated as more unpleasant (lower valence), more arousing, and elicited more corrugator EMG and skin conductance response than neutral pictures. By contrast, erotica pictures were generally rated as more pleasant, more arousing, and elicited greater skin conductance response than neutral. Both anger-in groups showed similar valence ratings and corrugator response to neutral and positive pictures. However, participants who scored high on anger-in rated negative pictures as less unpleasant (higher valence ratings) and displayed less corrugator EMG activity than the low anger-in group. Moreover, participants who scored high on anger-in reported more arousal in response to erotic pictures. Both groups displayed similar SCRs to pictures. *Statistically significant at p < .05. n.s. = nonsignificant.

Fig. 3.

Emotional modulation of pain (left graph) and nociceptive flexion reflexes (NFR, right graph) by mutilation, neutral, and erotica pictures in anger-in groups (low anger-in, high anger-in). Suprathreshold electric stimulations elicited higher pain ratings during mutilation pictures than neutral pictures, whereas electric stimulations elicited lower pain ratings during erotic pictures than neutral pictures. Both groups displayed similar pain modulation in response to picture contents, but the high anger-in group reported more overall pain in response to the electric stimulations. Suprathreshold electric stimulations elicited larger NFRs during mutilation pictures than neutral and erotic pictures. However, NFRs during neutral and erotic pictures did not significantly differ. There were no significant group differences in emotional modulation of NFR. *Statistically significant at p < .05. n.s. = nonsignificant

Fig. 4.

Attentional modulation of pain (left graph) and nociceptive flexion reflexes (NFR, right graph) by interpicture intervals (no picture) and neutral pictures (distractor) in anger-in groups (low anger-in, high anger-in). For the low anger-in group, pain ratings were lower during neutral pictures compared to no pictures, suggesting an effect of distraction/attention that inhibited pain. For the high anger-in group, pain ratings during no picture and neutral pictures were not significantly different; however, persons in the high anger-in group reported higher overall pain in response to the electric stimulations. NFRs were not significantly different between no pictures and neutral pictures in either group. *Statistically significant at p < .05. n.s. = nonsignificant

Fig. 5.

Anger inhibition in the context of James Gross’ (2002) modal model of emotion and process model of emotion regulation. This figure shows how anger inhibition may be a form of antecedent-focused emotion regulation that affects attentional deployment during emotion generation processes.