The Interaction Between Mental Distress and Opioid Maintenance Treatment Impacts Levels of Circulating Cytokines

Opioid use modulates parts of the immune system, including cytokines, but with disparate results. Furthermore, several studies have demonstrated a positive correlation between circulating proinflammatory cytokines and mental distress of various kinds. The aim of this study was to investigate the relationship between self-reported mental health symptoms and peripheral circulating cytokines in opioid maintenance treatment patients to see whether the previous disparate results could at least in part be explained by an interaction with mental distress. In a cross-sectional study, we investigated levels of 27 serum cytokines and chemokines using multiplex technology in 120 patients with chronic hepatitis C virus infection. Self-reported mental health symptoms were obtained using SCL-90-R. Among the nonopioid maintenance treatment patients, we found a positive correlation between self-reported mental health symptoms and peripheral circulating cytokines. An opposite trend was found for several of the proinflammatory cytokines in the opioid maintenance treatment patients, which was confirmed through linear regression analysis. We found an interaction between symptom scores and group affiliation on peripherally circulating cytokine levels for four of the cytokines. This report demonstrates that opioids seem to interact with self-reported mental health symptoms in a way that impacts levels of cytokines. We propose that opioids might be associated with a pro-inflammatory dampening and that this should be taken into consideration when analysing cytokine levels.