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.