Main findings
In this nationwide survey, the prevalence of moderate-to-severe symptoms of anxiety, depression, acute stress and insomnia was 25.9%, 36.9%, 13.6%, and 56.6%, respectively. Notably, the prevalence of symptoms of anxiety and depression during the Omicron wave was twofold higher than during the first wave of the COVID-19 pandemic1 and eightfold higher than before the COVID-19 pandemic in China.17 Additionally, the prevalence of moderate-to-severe insomnia was ninefold higher than in the first wave of the COVID-19 pandemic.1 However, the prevalence of acute stress related to COVID-19 was lower than in a previous online survey in China1; however, the screening tools used in the two surveys differed. In our study, 21.9% of anxiety, 19.2% of depression, 18.1% of acute stress and 10.7% of insomnia were theoretically attributed to epidemic-related factors. Among individual epidemic-related factors, the PAF order from greatest to smallest was as follows: perceived impact on social interactions>impact on accessibility to medical services>impact on quality of life>worries about the sequelae>worries about active COVID-19-related infection or re-infection. Notably, being actively infected contributed to a reduced risk of adverse mental health-related outcomes, differing from previous survey findings in China17 but consistent with other studies.18 Recovery from an infection of the virus and possibly a re-infection may have contributed to the reduced risk. Together, these findings suggest a profile of the population’s response to the wide-ranging upheavals experienced during the Omicron outbreak and provide evidence for the increased prevalence of adverse mental health-related outcomes. These results, along with other studies, can inform population-level mental health management and intervention strategies when responding to epidemic outbreaks.
Before the COVID-19 outbreak, depressive and anxiety disorders were the leading contributors to the global mental health burden.19 In China, the 12-month prevalence rates of depressive and anxiety disorders in the general population were 3.6% and 5.0%, respectively.17 The COVID-19 pandemic in 2020 substantially increased the prevalence and burden of major mood disorders.20 The prevalence of anxiety, depression, acute stress and insomnia in China increased dramatically during the first wave of the COVID-19 pandemic.1 21 However, China’s first wave of the COVID-19 pandemic was mainly limited to Hubei Province, as aggressive non-pharmaceutical public health interventions abated it quickly in early 2020.22 Unlike that outbreak, the Omicron wave at the end of 2022 rapidly spread to the entire country, disrupting many aspects of life for the entire population within a short period of one month. This was unlike other countries and regions where peaks of the SARS-CoV-2 Omicron wave ranged from several months to years.23 24 Therefore, the conditions in which the Chinese population was exposed to the Omicron variant differed from those in other countries and from the early pandemic conditions in China in early 2020. Our timely study during this wave suggests that the impact of the epidemic on the prevalence of major mental disorder symptoms was more substantial during the 2022–2023 outbreak than in 2020.
We systematically demonstrated the risk of mental health consequences associated with pandemic factors and estimated the proportion of mental health outcomes attributable to six pandemic-related factors in China. The impact people perceived on their social life, accessibility to medical services, quality of daily life, and worries about the sequelae, infection or re-infection were the top factors that contributed to mental health-related symptoms. Partially consistent with a previous report,25 these factors highlight the potential priorities for preventing mental disorders in pandemics. To date, no published research has estimated the PAF for mental health-related symptoms using epidemic factors. However, using different measures, the COVID-19 Mental Disorders Collaborators26 estimated that the global prevalence of depression and anxiety increased by 27.6% and 25.6%, respectively, in the general population during the COVID-19 pandemic.
Unlike previous studies that reported an association between self-reporting of COVID-19 and mental health deterioration27 and sleep quality,28 our study found that self-reported infection did not contribute to adverse mental health-related symptoms. We further found that participants who recovered from the illness were less likely to have symptoms of anxiety and insomnia than those who were actively ill. Additionally, participants who had re-infections were less likely to suffer from anxiety, depression and insomnia than those with a first-time infection. This finding provides new evidence that, for most people, adverse life events result in initial short-term increases in symptoms of mental distress, followed by recovery. Moreover, this pattern is consistent with the results of large-scale studies on COVID-19.29 Furthermore, the outbreak of the Omicron variant in China in December 2022 differed from that in other countries and regions. Most people in China were infected over a short period of time; however, in our study, their symptoms were mild to moderate, as 13.2% were asymptomatic, 81.6% had systemic symptoms, 62.6% had respiratory symptoms and 16.5% had gastrointestinal symptoms; only 7.2% of the participants experienced life-threatening shortness of breath. At the time of writing this article, the COVID-19 pandemic in China has declined drastically, according to a report from the National Health Commission of the People’s Republic of China.30
Limitations
First, given the nature of the online survey, most participants were young and highly educated, limiting the sample’s representativeness, especially that of older adults. Second, we relied on self-rating scales rather than clinical diagnoses to estimate the prevalence of common mental health-related symptoms. The prevalence estimates of common mental health-related outcomes assessed using screening tools are considerably higher than those from diagnostic interviews. Third, given the nature of this cross-sectional study, causal relationships between mental health-related symptoms and risk factors cannot be established.