The proposed study will assess the relationship between working conditions and the prevalence and incidence of major depression among nurse aides within 50 nursing homes in Ohio, West Virginia, and Kentucky. The overarching hypothesis of this three year study is that work organization (i.e., the amount of work to be performed and the capacity to decide how to do it) will have a direct effect on the prevalence and incidence of major depression among nurses aides. This will be the first study to examine work organization factors in nursing homes in relation to the prevalence and incidence of depression among nurse aides in the U.S. This study will also make important methodological contributions to the field of occupational health. Work organization will be measured at the individual and organization levels, and they will apply innovative statistical methods that are appropriate for the simultaneous analysis of two levels of data. The investigator will employ a newly created screening instrument for depression with the highest content validity among non-clinical assessments for this outcome. The results of this study will have implications for work place policies in nursing homes across the U.S. that have the potential to reduce depression and associated loss of productivity among nursing home workers.