To investigate the mental health status of security firm workers focusing on job stress, depressive symptoms, and overall psychosocial stress and to determine the relationship between depressive symptoms and the level of distress with changes in labor conditions and intensity.

Using a cross-sectional design, a formal survey including basic sociodemographic factors, job-related characteristics, job stress, psychosocial stress, depressive symptoms, and changes in labor conditions and intensity was conducted on workers employed in nine security firms. A total of 1,313 workers replied to the survey. We estimated the relationship between psychosocial stress and depressive symptoms with job stress, and changes in labor conditions and intensity by multivariate logisitic regression analysis.

Severe and intermediate level of depressive symptoms occurred in 18.5% (209) of the workers, and the high risk psychosocial distress groups accounted for 44.2% or the workers. Based on multivariate analysis, the Borg scale (OR=2.43 95%, CI=1.72–3.45), relative labor intensity (OR=1.05, 95% CI=1.00–1.09), high job demand (OR=1.47, 95% CI=1.06–2.06) were significantly associated with depressive symptoms. For psychosocial stress, the Borg scale (OR=2.39, 95% CI=1.84–3.10), relative labor intensity (OR=1.06, 95% CI=1.02–1.09), low job control (OR=1.80, 95%CI=1.38–2.35), and high job instability (OR=1.53, 95%CI=1.02–2.29) were significantly associated with high risk groups.

This study showed that a large proportion of security firm workers encountered depressive symptoms and psychosocial stress. Also, labor intensity and changes in labor condition (relative work intensity) were influential factors for depressive symptoms and psychosocial stress. Therefore, we conclude that not only an intervention for job stress should be offered, but also a policy toward the systemic problem of labor intensification should be considered.