Abstract
BACKGROUND: Global estimates suggest strained mental health during the first year of the COVID-19 pandemic, but the lack of nationally representative and longitudinal data with clinically validated measures limits knowledge longer into the pandemic. METHODS: Data from 10 rounds of nationally representative surveys from Denmark tracked trends in risk of stress/depression from just before the first lockdown and through to April 2022. We focused on age groups and men and women in different living arrangements and controlled for seasonality in mental health that could otherwise be spuriously related to pandemic intensity. RESULTS: Prior to first lockdown, we observed a "parent gap", which closed with the first lockdown. Instead, a gender gap materialized, with women experiencing higher risks than men-and higher than levels predating first lockdown. Older respondents (+ 70 years) experienced increasing risks of stress/depression early in the pandemic, while all other groups experienced decreases. But longer into the pandemic, risks increased for all age groups and reached (and sometimes exceeded) levels from before first lockdown. CONCLUSION: Denmark had low infection rates throughout most of the pandemic, low mortality rates across the entire pandemic, and offered financial aid packages to curb financial strains. Despite this circumstance, initial improvements to mental health during the first lockdown in Denmark were short-lived. Two years of pandemic societal restrictions correspond with deteriorating mental health, as well as a change from a parenthood gap in mental health before first lockdown to a gender gap two years into the pandemic.