Changes in exposure to positive leadership behaviours and subsequent changes in workers' depressive symptoms and risk of onset of antidepressant treatment

OBJECTIVES: Using consecutive waves of a Danish nationwide survey, we investigated in a quasi-experimental design whether changes in positive leadership behaviours were associated with subsequent changes in depressive symptoms and risk of antidepressant treatment.

METHODS: Sample 1 consisted of 6062 workers participating in 2012, 2014 and 2016. Sample 2 consisted of 15 619 workers participating in either 2012-2014 or 2016-2018. We measured leadership behaviours by an eight-item scale and depressive symptoms by the Major Depression Inventory (MDI) and linked register data on purchase of antidepressants. Using linear and logistic regression, we adjusted for covariates and estimated the association between changing levels of leadership behaviours and subsequent depressive symptoms and onset of antidepressant treatment.

RESULTS: In sample 1, changing from high to low levels of exposure to positive leadership behaviours from 2012 to 2014 was associated with a higher MDI score in 2016 (sample 1, regression coefficient: 1.12, 95% CI 0.68 to 1.56), whereas changing from low to high levels was associated with a lower MDI score (-1.84, 95% CI -2.51 to -1.17). In sample 2, ORs for antidepressant treatment ranged from 1.06 to 1.21 with wide CIs that included unity.

CONCLUSIONS: This study suggests that a decrease in positive leadership behaviours has a hazardous effect on workers' level of depressive symptoms, whereas an increase has a beneficial effect. There were no clear associations with antidepressant treatment.