Abstract
Introduction
Experimental evidence supports the hypothesis of reciprocal influence between neural systems involved in cognition and central pain processing circuits. Furthermore, studies have demonstrated bidirectional communication between central pain processing areas and the immune system, leading to changes in behaviour, sensory perception, mood, and cognition. However, the academic community has not yet reached a consensus on whether effective analgesic interventions can mitigate or reverse cognitive deterioration.
Methods
This systematic review evaluated the effectiveness of various therapeutic interventions in improving cognitive functions (primary outcome) and altering the profile of immunological markers (secondary outcome) in chronic pain patients. The review was limited to randomised controlled trials addressing chronic pain of any aetiology, with searches conducted in PubMed, EMBASE, and Scopus databases.
Results
The qualitative synthesis of twelve studies conducted between 2003 and 2021, involving 1432 participants in experimental (n = 950) and control (n = 482) groups, revealed some interesting patterns. Only half of the studies (6/12) reported cognitive improvement, with attention being the most analysed cognitive domain, followed by memory and executive function. Fibromyalgia was the most studied aetiology of chronic pain. The strategies of intervention/treatment and durations varied widely; however, milnacipran versus placebo emerged as the most frequently employed intervention. Only one study reported immunological markers, limiting the evaluation of this outcome.
Conclusion
Based on this analysis, it is not possible to affirm that interventions targeting chronic pain improve cognition. This review suggests new research directions and calls for more robust methodological approaches.
Get full access to this article
View all access options for this article.
References
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
