Objectives: There is a strong link between depression and chronic pain; however, less is known about how factors may influence depression in this population. The objective of this study was to identify predictors of depression in a sample of patients with chronic pain.
Design: In this cross-sectional study, individuals were recruited from a chronic pain clinic in Ontario, Canada. Sociodemographic data and clinical health information was collected. The following outcome measures were completed by patients: Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder 7 item (GAD-7); Pain Disability Index (PDI), Brief Pain Inventory (BPI) severity and interference, CAGE substance abuse screening tool, Anxiety Sensitivity Index (ASI), and Acceptance and Action Questionnaire (AAQ). Associations between all variables and the PHQ-9 were determined using hierarchical regression modelling.
Results: The sample consisted of 218 individuals (140 females, 78 males) with a mean age of 52.9±11.9 years and mean time since injury of 14.2±10.3 years. Time since injury, gender, living arrangement, and use of non-opioids were not correlated with depression. In the subsequent stepwise model, GAD-7 (R2 change=0.666; p< 0.001), BPI pain interference (R2 change=0.062; p< 0.001), ASI (R2 change=0.018; p=0.001), employment status (R2 change=0.009; p=0.016), AAQ (R2 change=0.008; p=0.019), and PDI (R2 change=0.008; p=0.021) were significant predictors of depression whereas age, type of pain, pain severity, education, cannabis use, morphine equivalent, and substance misuse use were not. The overall model fit was R2=0.770 (p=0.021).
Conclusions: Anxiety, pain interference, employment status, and pain disability in life activities was found to significantly predict depression in this chronic pain population. These factors should be considered when evaluating and treating depression in individuals with chronic pain.
Amanda McIntyre– Research Associate, Parkwood Institute Research, Parkwood Institute
Jerome Iruthayarajah– Research Associate, Parkwood Institute Research, Parkwood Institute
Swati Mehta– Scientist, Parkwood Institute Research, Parkwood Institute
Shannon Janzen– Research Associate, Parkwood Institute Research, Parkwood Institute
Sarah Caughlin– Research Associate, Parkwood Institute Research, Parkwood Institute
Eldon Loh– Physiatrist, St. Joseph's Health Care London
Robert Teasell– Physiatrist, Parkwood Institute Research, Parkwood Institute