The Prescription Opioids and Depression Pathways Cohort Study.

Background: Results from studies using medical record data indicate chronic (>90 days) opioid analgesic use (OAU) is associated with new depressive episodes (NDE), worsening depression and risk for depression recurrence. This body of evidence is based on retrospective cohort studies and medical record data. Limitations of existing research are overcome in a new prospective cohort study of the opioid-depression relationship.

Methods: Prospective cohort of 1500 adult patients recruited from two health care systems. Eligible subjects started a new period of OAU and have 30 to 90 days of OAU at baseline. Diagnostic assessments for psychiatric disorders, structured measures of pain, pain functioning, opioid use, social support, sleep and impulsivity will be obtained at baseline, 6-month and 12-month follow-up. Baseline participants will be invited to 12 monthly brief assessments of pain-related functioning, depression symptoms and opioid use.

Innovation: Robust control for confounding by indication and detailed phenotyping of depression and opioid use disorder.

Anticipated results: Chronic OAU will be associated with new onset of a depression phenotype characterized by anhedonia and somatic symptoms. This relationship will be partly, but not completely explained by impaired functioning and low social support.

Conclusions: Although the annual number of opioid prescriptions in the United States has decreased, over 190 million patients have OAU each year. If chronic OAU leads to a clinically meaningful affective disorder, independent of pain, then we need to consider depression an important adverse effect of chronic OAU and adjust care for chronic pain accordingly.