A longitudinal study of depression among middle-aged and senior patients initiating chronic opioid therapy.

Background: Improved understanding how depressive symptoms change with sustained opioid use is needed.

Methods: We prospectively assessed patients 45 years or older initiating chronic opioid therapy (COT) at baseline and at 4 and 12 months, differentiating recent COT initiators (n=748) and continuing users (n=468). Level of opioid use before 12-month follow-up was classified as regular/higher-dose, intermittent/lower-dose, or minimal/no use. Depressive symptoms were assessed using the Patient Health Questionnaire-8 (PHQ-8).

Results: Depressive symptoms decreased, on average, from baseline to 12 months regardless of level of opioid use. COT patients with regular/higher-dose compared to those with intermittent/lower-dose opioid use (who had similar pain outcomes) did not differ in PHQ-8 scores at 12 months (adjusted mean difference -0.14, 95% CI, -1.07, 0.78 for COT initiators). At 12 months, COT patients with intermittent/lower-dose use had higher adjusted PHQ-8 scores than did those with minimal/no opioid use (adjusted mean difference 0.77, 95% CI, 0.03-1.52 for COT initiators). However, 77% of patients who discontinued opioids cited improved pain as a reason for discontinuation, while 21% cited negative emotional effects of opioids as a reason for discontinuation. Discontinuation was more common among persons who, at baseline, attributed 3 or more depressive symptoms to opioid use.

Limitations: Results are relevant to older COT patients receiving low to moderate opioid doses.

Conclusions: Depressive symptoms did not increase with sustained opioid use. Depressive symptoms were not higher with regular/higher-dose compared to intermittent/lower-dose use. Persons who perceived negative effects of opioids on emotions more often discontinued their use.