Most studies report a positive relationship of work engagement with health and job performance, but, occasionally, a “dark side of engagement” has also been uncovered. The current longitudinal study among 1,967 Japanese employees confirmed that work engagement has a curvilinear relation with psychological distress. At low levels of engagement a favorable effect was found, but this disappeared at intermediate levels of work engagement, and, at higher levels, an adverse effect became prominent. In addition, work engagement had a curvilinear relation with in-role performance; the higher the levels of work engagement, the stronger the favorable effects on in-role performance. However, contrary to expectations, work engagement had a linear relation with psychological distress and creative behavior. Hence, the study results suggest that work engagement plays a different role in health enhancement compared to performance enhancement. Leveling-off and adverse effects of high work engagement were observed for psychological distress in the short and not in a long run. In contrast, no leveling-off effect of high work engagement was observed for job performance. Thus, except for the short-term effect on psychological distress, no dark side of work engagement was observed for psychological distress and job performance (Read more).