The most recent version of the job demands-resources (JD-R) theory proposes that demanding working conditions and employee strain form a self-perpetuating loss cycle. By acknowledging that such cycles are detrimental for both employees and organizations, the present study aimed to contribute to enhancing the current scarce understanding regarding their explanatory mechanisms. For this purpose, it applied social cognitive theory to propose that occupational self-efficacy mediates the effects of two role stressors (i.e., role ambiguity and role conflict) on employee mental health complaints and vice versa. The hypothesized reciprocal mediation effects were tested using a three-wave full panel research design and a dataset of 917 (NT1 = 513, NT1+T2 = 122, NT1+T3 = 70, NT1+T2+T3 = 212) Croatian employees working in heterogeneous private sector industries. The results demonstrated that role conflict, but not role ambiguity, undermined employees' beliefs in their capabilities to successfully master their jobs which, in turn, led them to experience more mental health complaints over time. Contrary to expectations, poor mental health did not lead to diminished efficacy beliefs nor, in turn, more job demands over time. Overall, the results of this study demonstrated an additional mechanism in the job demands-strain relationship and, at the same time, shed new light on the role of personal resources within the JD-R theory. Accounting for the malleable nature of employee efficacy beliefs, the study proposes several ways in which organizations can enhance occupational self-efficacy and thereby curb the causal chain linking job demands and employee strain reactions.
Keywords: job demands; job demands-resources theory; longitudinal study; mediation; mental health; occupational self-efficacy; social cognitive theory.