Perceived injustice (PI) has been identified as an important risk factor for pain-related outcomes. To date, research has shown that pain acceptance and anger are mediators of the association between PI and pain-related outcomes. However, a combined conceptual model that addresses the interrelationships between these variables is currently lacking. Therefore, the current study aimed to examine the potential mediating roles of pain acceptance and anger on the association between PI and adverse pain-related outcomes (physical function, pain intensity, opioid use status).
This cross-sectional study used a sample of 354 patients with chronic pain being treated at a tertiary pain treatment center. Participants completed measures of PI, pain acceptance, anger, physical function, pain intensity, and opioid use status. Mediation analyses were used to examine the impact of pain acceptance and anger on the association between PI and pain-related outcomes.
Examination of the specific indirect effects revealed that pain acceptance fully mediated the relationship between PI and physical function, as well as the relationship between PI and opioid use status. Pain acceptance emerged as a partial mediator of the relationship between PI and pain intensity.
This is the first study to provide a combined conceptual model investigating the mediating roles of pain acceptance and anger on the relationship between PI and pain outcomes. On the basis of our findings, low levels of pain acceptance associated with PI may help explain the association between PI and adverse pain outcomes. Clinical and theoretical implications are discussed.
*Department of Psychology, McGill University, Montreal, QC, Canada
†Stanford Systems Neuroscience and Pain Laboratory, Department of Anesthesiology, Perioperative and Pain Medicine, Division of Pain Medicine, Stanford University School of Medicine, Palo Alto, CA
Supported by the National Institutes of Health (NIH) NCCIH P01AT006651 (S.C.M.) and P01AT006651S1 (S.C.M. and B.D.D.); NCCIH R01AT008561 (B.D.D. and S.C.M.); NIDA K24 DA029262 (S.C.M.), NIH Pain Consortium HHSN271201200728P (S.C.M.); the Chris Redlich Pain Research Endowment (S.C.M.), and the Quebec Pain Research Network (J.S.C.). The authors declare no conflict of interest.
Reprints: Junie S. Carriere, PhD, Department of Psychology, McGill University, 1205 Dr Penfield, Montreal, QC, Canada (e-mail: firstname.lastname@example.org).
Received May 16, 2017
Received in revised form January 23, 2018
Accepted February 13, 2018