Association between job stress and depression among Japanese employees threatened by job loss in a comparison between two complementary job-stress models

Objectives This study compared the separate effects produced by two complem entary stress models - the job demand-control model and the effort-reward i mbalance model - on depression among employees threatened by job loss. Methods A cross-sectional analysis was conducted to examine these associati ons among 190 male and female employees who responded to a self-administere d questionnaire in a small Japanese plant with economic hardship. The emplo yees were engaged in 2 job types - direct assembly line and indirect suppor tive tasks and the latter was threatened by job loss because of downsizing. Independent variables were measured by the Japanese versions of Karasek's demand-control questionnaire and Siegrist's effort-reward imbalance questio nnaire. Depression was assessed by the Center for Epidemiologic Studies Dep ression Scale. Results The employees with indirect supportive tasks (target for downsizing ) were more Likely to have depressive symptoms than direct assembly-line wo rkers. Job strain, a combination of high demand and low control at work, wa s more frequent among the latter, while the combination of high effort and low reward was more frequent among the former. After adjustment for work en vironment factors, low control [odds ratio (OR) 4.7], effort reward imbalan ce (OR 4.1), and overcommitment (the person characteristic included in the effort-reward imbalance model) (OR 2.6) were independently related to depre ssion. There is some indication that these effects were particularly strong in the subgroup suffering from potential job loss. Conclusions This study confirms that the 2 job stress models identify diffe rent aspects of stressful job conditions. Moreover, effort-reward imbalance and low control at work are both associated with symptoms of depression.