Psychological Factors and Conditioned Pain Modulation: A Meta-Analysis

Area of Science:

• Neuroscience
• Psychology
• Pain Research

Background:

• Conditioned pain modulation (CPM) is a key endogenous analgesia mechanism.
• Psychological factors, including anxiety, depression, and pain catastrophizing, may influence CPM.
• Previous research has not consistently focused on the relationship between psychological factors and CPM.

Purpose of the Study:

• To systematically analyze the association between CPM responses and psychological factors.
• To investigate these associations in both pain-free individuals and patients with chronic pain conditions.

Main Methods:

• A comprehensive literature search was conducted on PubMed, identifying 37 relevant studies.
• Meta-analyses employed DerSimonian and Laird's random-effects model on Fisher's z-transforms of correlations.
• Publication bias was assessed using funnel plots and Egger's regression test.

Main Results:

• Overall, no significant correlations were found between general CPM responses and the psychological factors examined.
• A secondary analysis revealed modality-specific correlations in healthy individuals: pressure-based CPM with anxiety (r=-0.1087), heat-based CPM with depression (r=0.2443), and electrical-based CPM with pain catastrophizing (r=-0.1501).
• Confidence intervals for these modality-specific correlations did not include zero, indicating statistical significance.

Conclusions:

• Specific psychological factors are associated with modality-specific CPM responses in healthy individuals.
• These findings suggest that different CPM paradigms, based on stimulation modality, may engage distinct neural mechanisms.
• Further research is warranted to explore these modality-specific relationships in various clinical populations.