Abstract
BACKGROUND: In the multi-site Prescription Opioid Addiction Treatment Study (POATS), the best predictor of successful opioid use outcome was lifetime diagnosis of major depressive disorder. The primary aim of this secondary analysis of data from POATS was to empirically assess two explanations for this counterintuitive finding. METHODS: The POATS study was a national, 10-site randomized controlled trial (N = 360 enrolled in the 12-week buprenorphine-naloxone maintenance treatment phase) sponsored by the NIDA Clinical Trials Network. We evaluated how the presence of a history of depression influences opioid use outcome (negative urine drug assays). Using adjusted logistic regression models, we tested the hypotheses that 1) a reduction in depressive symptoms and 2) greater motivation and engagement in treatment account for the association between depression history and good treatment outcome. RESULTS: Although depressive symptoms decreased significantly throughout treatment (p <.001), this improvement was not associated with opioid outcomes (aOR = 0.98, ns). Reporting a goal of opioid abstinence at treatment entry was also not associated with outcomes (aOR = 1.39, ns); however, mutual-help group participation was associated with good treatment outcomes (aOR = 1.67, p <.05). In each of these models, lifetime major depressive disorder remained associated with good outcomes (aORs = 1.63-1.82, ps = .01-.055). CONCLUSIONS: Findings are consistent with the premise that greater engagement in treatment is associated with good opioid outcomes. Nevertheless, depression history continues to be associated with good opioid outcomes in adjusted models. More research is needed to understand how these factors could improve treatment outcomes for those with opioid use disorder.