in terms of reciprocal causality. On the basis of the Conservation of
Resources theory, the Broaden-and-Build theory, and previous studies, we hypothesized that the
relationships between work engagement and such variables are reciprocal over time. The study was
conducted among 157 schoolteachers, and the time lag was of five months on average. Results of structural equation-
modelling analysis showed that the model with reciprocal relationships exhibited the best fit
with the data. Specifically, work engagement at T1 predicted mental-health problems, job satisfaction, and
organizational citizenship behaviours at T2. Moreover, T1 mental-health problems were negatively related
to T2 work engagement, whereas T1 job satisfaction and T1 organizational-citizenship behaviours were
positively related to T2 work engagement. Overall, our findings provide evidence for a reciprocal influence
between engagement and these constructs, meaning that none of them can be considered as only a cause
or only a consequence.