# Stress-induced hyperalgesia instead of analgesia in patients with chronic musculoskeletal pain

**Authors:** Martin Löffler, Pia Schneider, Sigrid Schuh-Hofer, Sandra Kamping, Katrin Usai, Rolf-Detlef Treede, Frauke Nees, Herta Flor  
**arXiv:** [1902.07795](https://arxiv.org/abs/1902.07795)  
**Date:** 2019-02-20  
**Summary page:** https://www.summarizepaper.com/en/paper/1902.07795v2/

## Key points

- Chronic musculoskeletal pain (CMP) is common and often associated with impairments in pain-modulatory capacity.
- Stress plays a significant role in chronic pain, but it's unclear whether stress-induced analgesia (SIA) is affected in patients with CMP.
- A study was conducted on 22 patients with CMP and 18 pain-free participants to investigate this.
- Results showed that controls displayed a significant increase in pain threshold in response to the stressor, but patients with CMP showed no analgesia and increased pain intensity ratings after the stressor indicated hyperalgesia (SIH).
- There were no significant changes observed in pain tolerance or unpleasantness ratings after the stressor among both groups.
- Altered stress-induced pain modulation is an important mechanism involved in CMP, which needs further research to clarify its psychobiological mechanisms and contributing factors such as early childhood trauma, catastrophizing, comorbidity with mental disorders, and genetic predisposition.
- This study highlights new avenues for research into effective treatments for chronic musculoskeletal pain management.

## Summary

Chronic musculoskeletal pain (CMP) affects many individuals and is often associated with impairments in pain-modulatory capacity. While stress is known to play a significant role in chronic pain, it remains unclear whether stress-induced analgesia (SIA) is affected in patients with CMP. To investigate this, a study was conducted on 22 patients with CMP and 18 pain-free participants. Pain thresholds, pain tolerance, and suprathreshold pain ratings were examined before and after a cognitive stressor that typically induces pain reduction (SIA). The results showed that while the controls displayed a significant increase in pain threshold in response to the stressor, the patients with CMP showed no analgesia. Moreover, increased pain intensity ratings after the stressor indicated hyperalgesia (SIH) in the patients with CMP compared to controls. An exploratory analysis revealed no significant association of SIA or SIH with spatial pain extent. Interestingly, there were no significant changes observed in pain tolerance or unpleasantness ratings after the stressor among both groups. These findings suggest that altered stress-induced pain modulation is an important mechanism involved in CMP. Future studies need to clarify the psychobiological mechanisms of these stress-induced alterations in pain processing and determine the role of contributing factors such as early childhood trauma, catastrophizing, comorbidity with mental disorders, and genetic predisposition which may affect an individual's ability to experience SIA under stressful conditions. Overall, this study sheds light on how CMP can affect an individual's ability to experience SIA under stressful conditions and highlights new avenues for research into effective treatments for chronic musculoskeletal pain management.