The relationship between self-reported chronic stress, physiological stress axis dysregulation and medically-unexplained symptoms

Cardiac cycle modulates social pain

Social pain is a painful feeling evoked by social rejection, exclusion, or the loss of other important people. Previous research suggests that physical pain is reduced by increased signals from baroreceptors that monitor blood pressure. This pre-registered study investigated whether social pain is attenuated by increased baroafferent signals, as observed in physical pain. Given that baroafferent signals increase during cardiac systole and decrease during diastole, we hypothesized that feelings of pain induced by social rejection would be lower when exclusion events are presented at the cardiac systole than when they are presented at the diastole. Participants completed the cyberball task, a computerized ball-tossing game involving two other players. In the rejection condition, the ball was rarely thrown to the participant, while the other players kept tossing it to each other. Throws between other players were defined as exclusion events and were presented either at the cardiac systole (a systole condition) or at the diastole (a diastole condition). We found that exclusion events evoked significantly less social pain in the systole condition than in the diastole condition. Furthermore, the effects of cardiac cycle were more pronounced in participants with higher heart rate variability than those with lower heart rate variability. Our results suggest that cardiac afferent signals contribute not only to physical pain but also to social pain.

Subjective and physiological reactivity to emotional stressors in somatic symptom disorder

OBJECTIVE

We examined whether autonomic flexibility to experimentally presented stressors is reduced in somatic symptom disorder (SSD) as this would point to reduced vagal control as a proposed indicator of emotion regulation deficits.

METHOD

In this experimental study, the influence of health-related and social stressors on subjective and physiological reactivity was investigated in 29 subjects with SSD without any medical condition SSD(mc-), 33 subjects with SSD with medical condition SSD(mc+) and 32 healthy controls at the age from 18 to 70 years. Self-report and physiological variables were measured before and after/during stressor exposure, using state ratings of symptom intensity, disability, tension and mood, heart rate (HR), and heart rate variability (HRV).

RESULTS

Overall, the tension increased and the mood worsened after exposure to stressors compared to pre-exposure. Compared to HC, the two SSD groups showed higher symptom intensity, disability, tension and worse mood. The SSD(mc-) group revealed higher HR than HC (p = .012, d = -0.77). Compared to pre-exposure, symptom impairment increased after social stressor exposure in SSD(mc-) (p < .001, d = 1.36). HRV-root mean square of successive differences (RMSSD) only decreased in HC during exposure (p = .003, d = -1.09), not in the SSD groups. The two SSD groups did not differ in their reactivity to stressors.

CONCLUSION

HRV in SSD, seems to respond less flexibly to stressors, potentially reflecting overall physiological disturbance through reduced parasympathetic influence on HR. Stress reactivity in SSD(mc-) and SSD(mc+) do not seem to differ.