Introduction
As COVID-19 became a global pandemic, countries responded with nationwide lockdowns in attempt to slow and prevent further spread of the virus. With over half of the world population on some form of lockdown in April 2020, mental health of populations became a growing concern as individuals faced unprecedented levels of established mental health risk factors including social isolation, stress and anticipated economic hardship (Monroe and Simons, 1991; Mazure, 1998; Hammen, 2004; Ahnquist and Wamala, 2011; Matthews et al., 2016; Herbolsheimer et al., 2018; Economou et al., 2019; Brooks et al., 2020). These risk factors not only disproportionately affect individuals with a history of mental health problems (Hao et al., 2020; Yao et al., 2020), high-risk groups such as health care workers (Kang et al., 2020; Liu et al., 2020; Lu et al., 2020), COVID-19 patients and survivors (Zhang et al., 2020a), individuals with pre-existing chronic diseases (Ohliger et al., 2020; Wang et al., 2020b) or unemployed individuals (Zhang et al., 2020b), but also could trigger the onset of mental disorders in previously healthy populations. Alarming statements by public health experts and the United Nations have expressed the concern that COVID-19 could contribute towards a major global mental health crisis (Galea et al., 2020; UN, 2020).
Evidence on the prevalence of COVID-19-related mental health problems is emerging. A nationwide online survey of participants from China recruited through convenience sampling (n = 1210) reported that 16.5% of individuals exhibited severe depressive symptoms, and 28.8% moderate to severe anxiety symptoms (Wang et al., 2020a). Another nationwide online survey using convenient sampling in China estimated that the prevalence of anxiety disorders, depressive symptoms and reduced sleep quality was 35.1, 20.1 and 18.2%, respectively (Huang and Zhao, 2020). An online study (n = 4872) from Wuhan, China, found a 48.3 and 22.6% prevalence of depression and anxiety among the general adult population (Gao et al., 2020). The largest study conducted in China (n = 52 730) found 35% of respondents experienced psychological distress as assessed by the COVID-19 Peritraumatic Distress Index (Qiu et al., 2020). Nationwide studies from Bangladesh (Al Banna et al., 2020) and Taiwan (Wong et al., 2020) showed high prevalence of anxiety and depressive symptoms as well.
In Europe, several waves of the UK Household Longitudinal Study conducted between 2018/2019 and April 2020 (i.e. after approximately 1 month of lockdown in the UK) were compared, and it was demonstrated that the prevalence of clinically significant levels of mental disorders, as measured by the 12-item General Health Questionnaire, increased from 18.9 to 27.3% (Pierce et al., 2020). A nationwide study from Italy using convenience sampling (n = 500) reported that 19.4 and 18.6% of participants experienced mild and moderate-to-severe psychological distress respectively (Moccia et al., 2020). In Spain, respondents (n = 3480) of an online survey reported high prevalence of depression (18.7%), anxiety (21.6%) and post-traumatic stress disorder (15.8%) (González-Sanguino et al., 2020). High prevalence of depression (23.6%) and anxiety (45.1%) were also found in respondents (n = 343) of an online survey in Turkey (Özdin and Özdin, 2020). The nationally representative online survey which reported a baseline comparison comes from Denmark (n = 2458), where the WHO-5 Well-being Index was utilised finding that the Danish population, and especially females, reported lower emotional well-being during the pandemic than in 2016 (Sønderskov et al., 2020). In addition, recently published data from the United States demonstrated elevated levels of mental health problems among US adults; the presence of both, anxiety or depressive symptoms was about three times higher in June 2020 than in the second quarter of 2019, and substance use and suicidal ideation was elevated as well (Czeisler et al., 2020).
While the evidence suggests that COVID-19 is affecting population health negatively, no existing study has measured the prevalence of COVID-19-related mental illness on a nationally representative sample using an established psycho-diagnostic instrument, and existing studies lack a reliable baseline analysis against which it compares the prevalence of mental disorders to. We aimed to conduct a study aligned with the published mental health research priorities for the COVID-19 pandemic (Holmes et al., 2020), by assessing differences in the prevalence of current affective, anxiety and alcohol use disorders, and suicide risk screened using an established psycho-diagnostic instrument among a representative sample of Czech adults in 2017 and 2020.