Decreasing mental well-being during the COVID-19 pandemic: A longitudinal study among Danes before and during the pandemic

The COVID-19 pandemic has had a huge impact on people's lives and may influence mental health in the general population. In a unique representative Danish longitudinal study, we examined mental well-being measured just before and during the COVID-19 pandemic. The Danish Health and Wellbeing Survey is the Danish contribution to the European Health Interview Survey. In this study, we included the wave from autumn 2019, which we re-invited in the autumn 2020. The study population consisted of 4,234 persons. The main outcome was mental well-being measured by the Short Warwick-Edinburgh Mental Well-Being Scale (SWEMWBS). Linear and logistic regression models were conducted to evaluate change in SWEMWBS between 2019 and 2020. The SWEMWBS distribution was similar in 2019 and 2020, although the distribution moved to lower scores in 2020 compared to 2019. Mean SWEMWBS decreased significantly from 25.5 in 2019 to 24.6 in 2020 corresponding to a mean change of -1.0 (95%CI, -1.1. to -0.8). The proportion with low SWEMWBS increased from 16.5% in 2019 to 20.1% in 2020 (p < 0.001). The mean change was similar for men and women and for different age groups. The most negative development was observed among persons without depression or long-standing illnesses at baseline and among persons with higher educational level. Among persons with depression SWEMWBS increased. As expected, mental well-being significantly decreased in the adult Danish population during the COVID-19 pandemic. However, somewhat more unexpectedly, the decrease was most pronounced among persons without depression or long-standing illnesses and among higher educated groups.