It's giving me the blues: A fixed-effects and g-formula approach to understanding job insecurity, sleep disturbances, and major depression

Research suggests that work-related factors like job insecurity increases the risk of major depression (MD), although it is unclear whether the association is causal. Research further suggests that job insecurity increases sleep disturbances, which is also a risk factor for MD. Based on current knowledge, it is possible that job insecurity operates through sleep disturbances to affect MD, but this pathway has not been examined in the literature. The current study extends the literature by using two complementary, counterfactual approaches (i.e., random- and fixed-effects regression and a mediational g-formula) to examine whether job insecurity causes MD and whether sleep disturbances mediate the relationship. A methodological triangulation approach allowed us to adjust for unobserved and intermediate confounding, which has not been addressed in prior research. Findings suggest that the relationship between job insecurity and MD is primarily direct, that hypothetically intervening on job insecurity (in our g-formula) would reduce MD by approximately 10% at the population level, and this relationship operates via sleep disturbances to some degree. However, the indirect pathway had a high degree of uncertainty.