Prediction of new major depressive symptoms from long work hours, psychosocial safety environment, and work engagement: a population-based cohort study. 

Zadow AJ, Dollard MF, Dormann C et al. Prediction of new major depressive symptoms from long working hours, psychosocial safety environment, and work engagement: a population-based cohort study BMJ Open 2021; 11: e044133. doi: 10.1136/bmjopen- 2020-044133

Commentary

This study sought to assess the association of long working hours, psychosocial safety climate (PSC), work engagement (WE) and others with emerging major depressive symptoms over the next 12 months.

Study 1 had 3921 respondents; participants who were self-employed, temporary temporary, unclassified, working less than 35 hours/week (37% of 2850), and participants with major depressive symptoms in Study 1 (6.7% of 1782) were removed.

These results showed that long working hours were not significantly associated with new cases of major depressive symptoms, but when minor cases were excluded, those in the 41-48 hours and 55+ hours long working hours categories were positively associated with major depressive symptoms.

Low PSC was associated with a threefold increase in the risk of new major depressive symptoms, but not with long working hours, and long working hours did not mediate the relationship between PSC and new cases of major depressive symptoms.

The inverse relationship between PSC and major depressive symptoms was stronger in men than in women, confirming that WE is positively associated with long working hours.

Longer work hours (41-48 hours and >55 hours) mediated the positive relationship between WE and symptoms of major depression when minor cases of major depression were eliminated.

The researchers conclude that low workplace PSC and potentially long working hours (41-48; 55 hours/week or more) suggest an increased risk of new major depression symptoms.