Papers of the Week

Retrospective cohort studies have consistently observed that long-term prescription opioid use is a risk factor for new major depressive episodes. However, prospective studies are needed to confirm these findings and to establish evidence for causation. The Prescription Opioids and Depression Pathways cohort study is designed for this purpose. The present report describes the baseline sample and associations between participant characteristics and odds of daily vs. non-daily opioid use. Second, we report associations between participant characteristics and odds of depression, dysthymia, anhedonia, and vital exhaustion. Patients with non-cancer pain were eligible if they started a new period of prescription opioid use lasting 30 to 90 days. Participants were 54.8 (SD±11.3) years of age, 57.3% female and 73% white race. Less than college education was more common among daily vs. non-daily opioid users (32.4% vs. 27.3%; p=0.0008), as was back pain (64.2% vs. 51.3%; p<0.0001), any non-opioid substance use disorder (12.8% vs. 4.8%; p<0.0001) and current smoking (30.7% vs. 18.4% p<0.0001). High pain interference (50.9% vs. 28.4%; p<0.0001) was significantly associated with depression, as was having more pain sites (6.9±3.6 vs. 5.7±3.6; p<0.0001), and benzodiazepine co-mediation (38.2% vs. 23.4%; p<0.0001). High pain interference was significantly more common among those with anhedonia (46.8% vs. 27.4%; p<0.0001) and more pain sites (7.0±3.7 vs. 5.6±3.6; p<0.0001) were associated with anhedonia. Having more pain sites (7.9±3.6 vs. 5.5±3.50; p<0.0001) was associated with vital exhaustion as was back pain (71.9% vs. 56.8%; p=0.0001) and benzodiazepine co-medication (42.8% vs. 22.8%; p<0.0001). Patients using prescription opioids for non-cancer pain have complex pain, psychiatric, and substance use disorder comorbidities. Longitudinal data will reveal whether long-term opioid therapy leads to depression or other mood disturbances such as anhedonia and vital exhaustion. PERSPECTIVE: This study reports baseline characteristics of a new prospective, non-cancer pain cohort study. Risk factors for adverse opioid outcomes were most common in those with depression and vital exhaustion and less common in dysthymia and anhedonia. Baseline data highlight the complexity of patients receiving long-term opioid therapy for non-cancer pain.