Unrewarding work and major depressive episode: Cross-sectional and prospective evidence from the U.S. MIDUS study.

Depression is a serious mental health condition and is the leading cause of disability worldwide. Previous research has demonstrated that work stress may contribute to the development of depression through psychophysiological pathways. The present study assessed associations of work stress - in terms of the effort-reward imbalance (ERI) model measuring unrewarding work - with major depressive episode (MDE). Data were from the Mid-life in the United States study, a national, population-based sample of U.S. workers with 9-year follow-up prospective cohort design. The cross-sectional sample at baseline had 2204 workers, and the prospective sample had 1591 workers at follow-up (78.7% follow-up rate). Multivariable Bayesian logistic regression and Poisson regression were applied for examining cross-sectional and prospective associations, respectively. ERI was assessed by a validated 17-item scale at baseline, and MDE in the past 12 months was assessed by the Composite International Diagnostic Interview Short Form at both baseline and follow-up. It was found that ERI at baseline was associated with higher odds of prevalent MDE in the cross-sectional sample (OR = 1.47, HPD interval [1.26-1.69]), and with higher risk of MDE at follow-up in the prospective sample (RR = 1.29, HPD interval [1.01-1.60]). In both cross-sectional and prospective analyses, strongest associations were observed among workers with the highest quartile of ERI, after adjusting for demographic, socioeconomic, lifestyle, and other psychosocial factors. The stable and robust findings strengthen and extend previous findings that unrewarding work is a risk factor of mental health. If confirmed by further evidence, intervention targeting work stress reduction is warranted.