A reduced response to acute psychosocial stress in the chronic musculoskeletal pain patients

Abstract

Purpose of the research

Chronic musculoskeletal pain may be influenced by a number of factors, including contextual and psychological factors, the presence of comorbidities, and coping strategies. The relationship between chronic pain and psychosocial disorders is being supported by increasing evidence. The aim of this study was to evaluate the physiological responses to acute psychosocial stress caused by the Trier Social Stress Test (TSST) in musculoskeletal pain patients and healthy individuals.

Methods

Twenty-one chronic musculoskeletal pain patients and 22 healthy individuals participated in the study. Physiological measurements, including salivary cortisol, both linear and non-linear features of heart rate variability, and galvanic skin response, were recorded before, during, and after the TSST, as well as 20 min after recovery.

Major findings

The two-way mixed-model ANCOVA (with age considered as a covariate) showed that the response to acute stress differed between the two groups. Salivary cortisol levels increased in the healthy group after stress (from pre-stress = 13.38 ± 4.6 to post-stress = 15.07 ± 3.7) (p < 0.001) but tended to decrease in the musculoskeletal pain patients' group (from pre-stress = 15.02 ± 3.9 to post-stress = 13.77 ± 3.7). Among the parameters of heart rate variability, the mean RR interval (R-wave peak to R-wave peak in electrocardiograms) was significantly reduced during stress and returned to baseline after recovery, while the magnitude of change was smaller in the musculoskeletal pain patients' group (P < 0.05). The Wilcoxon test showed that the galvanic skin response significantly increased in both groups (p < 0.001).

Conclusions

The results suggest that chronic musculoskeletal pain decreases the body's stress system response to acute stress. These insights have implications for personalized treatment approaches by considering the status of stress system response and stress management strategies for chronic musculoskeletal pain patients.