BACKGROUND:
Job insecurity is a salient workplace stressor that may contribute to anxiety and depressive symptoms. However, the within-person dynamic relationships among job insecurity, anxiety, and depressive symptoms over time—especially when measurement intervals are unequal—are not well understood.

METHODS:
Three-wave longitudinal data were collected from employees in a large automobile manufacturing plant in China, with assessments at 0, 8, and 12 months. Internal consistency was evaluated for job insecurity (JIS), anxiety (ANX), and depressive symptoms (DEP). Longitudinal measurement invariance was tested using confirmatory factor analysis. Dynamic within-person associations among JIS, ANX, and DEP were estimated using a multivariate continuous-time structural equation model (ctSEM) in a Bayesian framework, allowing unequal time gaps between measurements.

RESULTS:
Reliability was high across waves (Cronbach’s alpha = 0.926–0.966). Mean levels of ANX and DEP were relatively low and stable across waves, whereas JIS was higher and showed a slight decline over time. In ctSEM, all constructs demonstrated significant negative self-effects (JIS: beta = −0.31, 95% credible interval [−0.48, −0.14]; ANX: beta = −0.60, [−1.01, −0.20]; DEP: beta = −1.17, [−1.60, −0.78]), indicating a tendency to return toward individual baseline levels. Higher JIS predicted subsequent increases in ANX (beta = 0.22, [0.10, 0.33]) and DEP (beta = 0.21, [0.10, 0.32]). ANX also strongly predicted increases in DEP (beta = 0.80, [0.43, 1.20]). Paths from ANX or DEP back to JIS were weaker, with credible intervals including zero.

CONCLUSIONS:
Among employees in a large automobile manufacturing plant, elevated job insecurity dynamically precedes increases in anxiety and depressive symptoms at the within-person level. Workplace strategies that reduce perceived job insecurity may help prevent short-term deterioration in employee mental health.