Changes in Mental Health During the COVID-19 Pandemic

An Analysis of Data From the German National Cohort (NAKO) for the Years 2014–2022

Background: The COVID-19 pandemic and its effects have aroused concern all over the world about its impact on mental health. The German National Cohort (NAKO) lends an opportunity to examine trends in altered mental health among adults in Germany during the pandemic.

Methods: We analyzed data from 79 239 participants in the NAKO study who were surveyed with respect to depressive and anxiety symptoms, stress, and self-perceived health at three points in time: at baseline (2014–2019) and in the early (2020) and late (2022) stages of the pandemic. Changes in mental health over time were analyzed with descriptive statistics, Sankey diagrams, and a post-hoc multinomial logistic regression.

Results: We observed an initial improvement in self-perceived health from baseline to 2020, but a deterioration from 2020 to 2022. The mental health of most participants remained the same over time. From baseline to 2022, the percentage of participants reporting depressive symptoms rose from 5.9% to 9.7%; rises were also seen in moderate to severe anxiety symptoms, from 3.9% to 6.2%, and in moderate to severe stress, from 4.1% to 10.2%. Both among young adults and among women, deterioration in self-perceived health was more common than improvement.

Conclusion: Our findings indicate a rise in mental health symptoms among adults in Germany during the pandemic. These findings underscore the need for continuous monitoring and targeted strategies to improve public mental health.

Cite this as: Wang Y, Xi Y, Breitner-Busch S, Padberg F, Rachow A, Brenner H, Castell S, Harth V, Haug S, Khattak MNK, Koch-Gallenkamp L, Krist L, Lampl BMJ, Lange B, Leitzmann M, Lieb W, Meinke-Franze C, Mikolajczyk R, Velásquez IM, Obi N, Övermöhle C, Pfrommer L, Pischon T, Rach S, Schmidt B, Willich SN, Huemer MT, Peters A: Changes in mental health during the COVID-19 pandemic: An analysis of data from the German National Cohort (NAKO) for the years 2014–2022. Dtsch Arztebl Int 2026; 123: 93–6. DOI: 10.3238/arztebl.m2025.0218

The outbreak of the COVID-19 pandemic—particularly the prolonged restrictions and the consequences thereof—aroused global concerns about the impact on mental health. The study presented here explored longitudinal data from the German National Cohort (NAKO) to analyze changes in depressive and anxiety symptoms, stress, and self-perceived health from baseline (2014–2019) through 2020 and 2022. We aimed to depict changes in mental health among German adults during the pandemic and identify which groups were resilient and which were negatively affected.

Methods

This study is based on the data of 205 415 adults aged 19–74 years from the NAKO, Germany’s largest prospective population-based cohort study (1). Between 2014 and 2019, 1.3 million individuals were invited to participate in the baseline examination, with an overall response rate of 15.6% (2). NAKO further conducted two supplementary surveys during and after the early phase of the COVID-19 pandemic. Between 30 April and 30 June 2020, a pandemic-related questionnaire was sent to all participants via email or letter. A total of 160 227 questionnaires (1) were completed (response rate 80.6%). Between September and December 2022, an additional online pandemic-related questionnaire was sent to 150 722 participants with a valid email address (3), of whom 110 375 (73.2%) completed it.

We included 79 239 participants with complete data on demographic variables and outcomes at all three time points (baseline, 2020, and 2022). We assessed four mental health outcomes (4): anxiety symptoms (assessed with Generalized Anxiety Disorder 7-item [GAD-7]), depressive symptoms (Patient Health Questionnaire-9 [PHQ-9]), stress (Patient Health Questionnaire stress scale [PHQ-stress]), and self-perceived health (five-point scale from bad to excellent). Participants were categorized into trajectory groups based on changes in their mental health between the three time points. Sankey diagrams were used to visualize the dynamics of changes in self-perceived and mental health. Post-hoc multinomial logistic regression examined associations between demographic factors and mental health trajectories. All analyses were conducted using R version 4.3.1.

Results

At baseline, the median age was 49 years (interquartile range 41–57 years). Altogether, 40 130 participants (50.6%) were women and 49 306 (62.2%) had a high level of education.

While many participants reported no change in mental health, 36.5% of participants reported very good self-perceived health at baseline, increasing to 44.4% in 2020, then falling below baseline to 30.5% in 2022. The proportion of persons reporting less good health decreased slightly from baseline to 2020, but doubled by 2022 compared with baseline levels (Figure). From baseline to 2022, the proportion of persons reporting depressive symptoms increased from 5.9% to 9.7%. In the same period, the proportion reporting moderate to severe anxiety symptoms rose from 3.9% to 6.2%, and moderate to severe stress from 4.1% to 10.2%. Furthermore, the three mental health outcomes showed an increase from different baseline years to 2020 and 2022 (eTable 1). The proportion of participants with poorer mental health on all three symptom scales increased from 1.3% (n = 1004) at baseline to 3.0% (n = 2370) in 2022. The proportion of symptom-free participants decreased from 91.1% at baseline to 83.9% in 2022 (eTable 2).

Figure 1

Sankey diagram of changes in self-perceived health and mental health over three time points

eTable 1

Changes in self-perceived health and mental health, stratified by baseline participation year (N = 79 239)

eTable 2

Distribution of overlapping of mental health symptoms across three time points (N = 79 239)

65% of participants reported changes in their self-perceived health (Table). Of those, 21.2% reported an improvement in the early phase of the pandemic (baseline to 2020), followed by a deterioration in the later phase (2020 to 2022). In contrast, most participants experienced no change in depressive symptoms (84.8%), anxiety symptoms (89.3%), and stress (83.9%). The second most common trajectory (depressive symptoms 5.0%, anxiety symptoms 3.5%, stress 5.4%) showed no change from baseline to 2020, but deterioration from 2020 to 2022.

Table

Trajectories of self-perceived and mental health over three time points (N = 79 239)

Middle-aged adults (40–59 years) reported improvement in self-perceived health more often than deterioration. In comparison, more younger adults (< 40 years) experienced deterioration in self-perceived health than improvement (eTable 3). Additionally, women and persons with lower levels of education were more prone to fluctuations in depressive symptoms, anxiety symptoms, and stress than men or those with higher levels of education. The post-hoc multinomial regression analysis suggested that middle-aged and older persons experienced deterioration in self-perceived health less frequently than their younger counterparts. Moreover, middle age was associated with decreasing stress symptoms (eTable 4).

eTable 3

Demographic characteristics of the trajectories in self-perceived and mental health across three time points (N = 79 239)

eTable 4

Post-hoc multinomial logistic regression of the changes in self-perceived and mental health across three time points (N = 79 239)

Discussion

The findings of this study suggest deterioration in mental health during the late phase of the COVID-19 pandemic in Germany. However, the overall trend of this deterioration was modest, and most participants reported no change in mental health.

We observed an initial increase in self-perceived health from baseline to 2020 (more very good, fewer less good) but then a deterioration from 2020 to 2022 (fewer very good, more less good). In contrast, the proportion of participants with depressive, moderate/severe anxiety symptoms, and stress showed a continuous increase across the three time points. This trend partly aligns with previous findings by Ahmed et al. (5), who reported an initial increase in the prevalence of some mental health problems during the early phase of the pandemic in Europe, which subsequently decreased by the end of 2020. In contrast to previous studies that showed a deterioration in mental health, our findings suggest an initial increase in self-reported mental health compared with before the pandemic, followed by a decline in the late pandemic phase. This may be attributable to broader and accumulating health impacts of the pandemic, including interrupted care for chronic conditions, long COVID, and lifestyle changes during lockdowns. In the meantime, other events such as the war in Ukraine, the resulting energy crisis, and worsening economic conditions occurred (6). Although most COVID-19 restrictions had been lifted, some COVID-19-related restrictions remained in place in 2022, and this may also have influenced mental health during the later phase (7). Furthermore, seasonal variation (8) may also have influenced the comparison between 2020 (spring) and 2022 (autumn).

Younger adults and women experienced greater mental health deterioration and had higher odds of deterioration in self-perceived health. This could point to heightened vulnerability to the pandemic‘s psychological, social, and economic consequences, which could include, for example, income loss, working from home, and caregiving or home-schooling responsibilities. A previous study based on NAKO data up to 2020 (4) also reported that individuals under 60 years of age, particularly those aged 20–39 years, reported more severe mental health impacts. The present study extends those results by observing lasting adverse mental health changes until fall 2022. Persons with a lower educational level were more likely to experience mental health changes. Potential contributing factors to varying mental health changes across different sociodemographic groups might include more pandemic-related stressors, economic difficulties, interpersonal conflicts, and less developed coping mechanisms (4, 9, 10, 11).

Our study further highlights that during the COVID-19 pandemic in Germany, deterioration in mental health and self-perceived health was more prevalent than improvement up to 2022. The frequent co-occurrence of symptoms from all three dimensions of mental health additionally suggests increased symptom overlap. The limitations of this study include the fact that some population groups, such as persons with lower educational level and a migration background, were underrepresented in the NAKO baseline data (2) and in this analysis.

Future research should explore the underlying mechanisms connecting global crises such as the pandemic to changes in mental health and develop intervention and prevention tools tailored to the identified at-risk populations.

Affiliation of the remaining authors

Ethics

The German National Cohort (NAKO) is performed with the approval of the relevant local ethics committees and is in accordance with national law and with the Declaration of Helsinki of 1975 (in the current, revised version). Written informed consent was obtained from all participants.

Funding

This project was conducted with data (Application No. NAKO-807) from the German National Cohort (NAKO) (www.nako.de). The NAKO is funded by the Federal Ministry of Education and Research (BMBF) [project funding reference numbers: 01ER1301A/B/C, 01ER1511D, 01ER1801A/B/C/D and 01ER2301A/B/C], federal states of Germany and the Helmholtz Association, the participating universities and the institutes of the Leibniz Association. We thank all participants who took part in the NAKO study and the staff of this research initiative. The work was further supported by the DZPG (German Centre for Mental Health) and by the BMBF (German Ministry of Education and Research) grant 01EE2303E. This work was supported by a scholarship under the State Scholarship Fund by the China Scholarship Council (File No. 202308210125).

Conflict of interest statement

AR has received financial support from the Free State of Bavaria for the COVID-19 study on the long-term cardiopulmonary and socioeconomic consequences in patients from South Africa.

TP is a member of the executive committee of NAKO e.V., which leads the NAKO study.

The remaining authors declare that no conflict of interest exists.

Manuscript received on 9 June 2025, revised version accepted on 18 November 2025

Corresponding author
Yanding Wang

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