The impact of the initial and second national COVID-19 lockdowns on mental health in young people with and without pre-existing depressive symptoms

Abstract

Background: The evidence on mental health during COVID-19 evolved fast, but still little is known about the long-lasting impact of the sequential lockdowns. We examine changes in young people's mental health from before to during the initial and second more prolonged lockdown, and whether women and those with pre-existing depressive symptoms were disproportionally impacted.

Methods: Participants reported on mental health indicators in an ongoing 18-year data collection in the Danish National Birth Cohort and in a COVID-19 survey, including 8 data points: 7 in the initial lockdown, and 1 year post. Changes in quality of life (QoL), mental well-being, and loneliness were estimated with random effect linear regressions on longitudinal data (N = 32,985), and linear regressions on repeated cross-sections (N = 28,579).

Findings: Interim deterioration in mental well-being and loneliness was observed during the initial lockdown, and only in those without pre-existing depressive symptoms. During the second lockdown, a modest deterioration was again observed for mental well-being and loneliness. QoL likewise only declined among those without pre-existing symptoms, where women showed a greater decline than men. QoL did not normalise during the initial lockdown and remained at lower levels during the second lockdown. These findings were not replicated in the repeated cross-sections.

Interpretation: Except for an interim decrease in mental health, and only in those without pre-existing depressive symptoms, this study's findings do not suggest a substantial detrimental impact of the lockdowns.

Keywords: COVID-19; Depressive symptoms; Lockdown; Longitudinal data; Mental health; Young people.

Fig. 1

The data set up presented according to the development of the COVID-19 pandemic and following lockdowns in Denmark.

Fig. 2

Mean change from pre-to during lockdown [95% CI] in QoL and mental well-being, and proportion of change in loneliness stratified by gender and pre-existing depressive symptoms, respectively (longitudinal setup).

Fig. 3

Regression of changes in QoL, mental well-being, and loneliness from pre-to during lockdown (longitudinal setup). *Repeated measures Random effect estimates and 95% CI presented (N = 32,985) (Total number including repeated measures N = 62,081) All models were weighted by IPW baseline population 1, Fig. S2 (N = 67,346) p-value for interaction between lockdown, gender, and pre-existing depressive symptoms (wave 1–8): QoL (p < 0·001), mental well-being (p < 0·001), and loneliness (p < 0·001).

Fig. 3

Regression of changes in QoL, mental well-being, and loneliness from pre-to during lockdown (longitudinal setup). *Repeated measures Random effect estimates and 95% CI presented (N = 32,985) (Total number including repeated measures N = 62,081) All models were weighted by IPW baseline population 1, Fig. S2 (N = 67,346) p-value for interaction between lockdown, gender, and pre-existing depressive symptoms (wave 1–8): QoL (p < 0·001), mental well-being (p < 0·001), and loneliness (p < 0·001).

Fig. 3

Regression of changes in QoL, mental well-being, and loneliness from pre-to during lockdown (longitudinal setup). *Repeated measures Random effect estimates and 95% CI presented (N = 32,985) (Total number including repeated measures N = 62,081) All models were weighted by IPW baseline population 1, Fig. S2 (N = 67,346) p-value for interaction between lockdown, gender, and pre-existing depressive symptoms (wave 1–8): QoL (p < 0·001), mental well-being (p < 0·001), and loneliness (p < 0·001).

Fig. 4

Mean/proportion [95% CI] of QoL, mental well-being, and loneliness stratified by gender and depressive symptoms, respectively (repeated cross-sectional setup).

Fig. 5

Regression of changes in QoL, mental well-being, and loneliness from pre-to during lockdown (repeated cross-sectional setup). Adjusted estimates and 95% CI are presented (N = 28,579) *Adjusted for gender and period **Adjusted for gender, period, household socio-occupational status, maternal age at childbirth, maternal smoking during pregnancy, educational enrolment, and housing composition. All models were weighted by IPW baseline population 2, Fig. S2 (N = 58,638) p-value for interaction between lockdown and depressive symptoms: QoL (p < 0·001), mental well-being (p = 0·3365), and loneliness (p < 0·001).