A temporal relationship between nonmedical opioid Use and major depression in the U.S.: A Prospective study from the National Epidemiological Survey on Alcohol and Related Conditions

•Both symptoms of major depression and major depression diagnosis predict the new onset of Non-medical opioid use in the US population•Past-year non-medical use of opioids predicts the new onset of symptoms of major depression, but not the major depression diagnosis in the US population•Early identification and intervention on the progress of major depression among opioid users may reduce non-medical opioid use. In addition, opioid misuse monitoring programs targeting people suffering from depression help alleviate their mental conditions. Given the existing strong cross-sectional relationship between nonmedical opioid use (NMOU) and major depressive disorder (MDD), this study focused on the temporal relationship between NMOU and major depression. Data sources were derived from Wave 1 and Wave 2 of the National Epidemiological Survey on Alcohol and Related Conditions. Logistic regression was applied to predicted NMOU at the follow-up survey based on baseline MDD diagnosis and symptoms of MDD among the sample without lifetime NMOU at baseline (N=32,982). In parallel, we examined the relationship between past year NMOU at baseline and new onset of MDD diagnosis (N=28,649) and between past year NMOU at baseline and new onset of symptoms of MDD (N=23,214) among people without major depression diagnosis or symptoms at baseline. MDD diagnosis (aOR=1.68, 95% CI=1.43, 1.98) and symptoms of major depression (aOR=1.25, 95% CI=1.14, 1.38) at baseline were associated with higher odds of incident NMOU. The baseline NMOU was associated with lower odds incident MDD diagnosis (aOR=0.79, 95%CI=0.66, 0.94) in the adjusted model. However, the baseline NMOU was associated with higher odds of new onset of major depressive symptoms at wave 2 in the sample without baseline symptoms of MDD (aOR=1.42, 95%CI=1.23, 1.63). Symptoms of MDD and MDD diagnosis increased the new onset of NMOU, while NMOU only increased the risks of new onset of symptoms of MDD.