Organisational justice protects against the negative effect of workplace violence on teachers' sleep: a longitudinal cohort study.

Objectives: This study aimed to examine the longitudinal association of workplace violence with disturbed sleep and the moderating role of organisational justice (ie, the extent to which employees are treated with fairness) in teaching.

Methods: We identified 4988 teachers participating in the Finnish Public Sector study who reported encountering violence at work. Disturbed sleep was measured in three waves with 2-year intervals: the wave preceding exposure to violence, the wave of exposure and the wave following the exposure. Data on procedural and interactional justice were obtained from the wave of exposure to violence. The associations were examined using repeated measures log-binomial regression analysis with the generalised estimating equations method, adjusting for gender and age.

Results: Exposure to violence was associated with an increase in disturbed sleep (RR 1.32 (95% CI 1.15 to 1.52)) that also persisted after the exposure (RR 1.26 (95% CI 1.07 to 1.48)). The increase was higher among teachers perceiving the managerial practices as relatively unfair (RR 1.46 (95% CI 1.01 to 2.09) and RR 1.59 (95% CI 1.04 to 2.42) for interactional and procedural justice, respectively). By contrast, working in high-justice conditions seemed to protect teachers from the negative effect of violence on sleep.

Conclusion: Our findings show an increase in sleep disturbances due to exposure to workplace violence in teaching. However, the extent to which teachers are treated with justice moderates this association. Although preventive measures for violence should be prioritised, resources aimed at promoting justice at schools can mitigate sleep problems associated with workplace violence.