Interaction between the Effects of Employment Instability in Combination with Economic Status on Depression

Background: As a result of flexibility of labor market, the number of temporary workers has been increasing, and their unstable employment status threatens their economic status in Korea. Both job instability and economic status have been reported as risk factors for depression. However, little is known about the interaction between the two, particularly in longitudinal studies. We investigated the interaction between the effects of employment stability during 3 years in combination with economic status on depression.

Methods: Based on the 1st(2005) through 4th(2008) wave data from KOWEPS(Korea WElfare Panel Study), data of 1,963 workers was analyzed. Employment instability was classified with four categories according to the employment status changes. Economic status was defined using disposable income and depression level was measured by CES-D.

Results: Groups of employment instability consisted maintaining regular worker(n=1,094), downward(n=135), upward,(n=368), and maintaining temporary worker(n=366). The result showed that (1) compared to the group of maintaining regular worker(13.25±4.20), the depressive level by CES-D was worse in the maintaining temporary worker group(15.07±.15, p<0.001). (2) As the disposable income was higher, the depressive level got lower(correlation coefficient -0.149, p<0.0001). (3) Statistically significant interaction effect was detected between employment instability and economic status(disposable income) on depression. Workers in downward group(β=-0.050, p<0.01) and maintaining temporary worker group(β=-0.079, p<0.001) showed decreasing depression level than maintaining stable workers as their disposable income increased.

Conclusion: These findings suggest that it is necessary to understand the severity of depression caused by unstable employment, and mental health policy should address those with unstable employment status and low economic situation.