Does COVID-19 psychological fatigue exist? Results of three online cross-sectional studies conducted in Spain from April 2020 to March 2021

Background A previously published meta-analysis found that about one-third of the general population experienced some mental health problem during the early phase of the COVID-19 pandemic, potentially leading to a late mental health crisis. We aimed to describe the acute, shortterm, and long-term effects of the COVID-19 pandemic on mental health. Methods A one-year online survey (S) was conducted in Spain (April 2020 -March 2021). We recruited 18 180 subjects using a virtual respondent-driven snowball sampling method (S1 April 2020, n = 6108; S2 October -November 2020, n = 6418; S3 March 2021, n = 5654). Participants completed the Spanish Depression, Anxiety, and Stress Scale (DASS-21). Results Overall, our results suggest a progressive increase in the prevalence of anxiety and stress throughout the pandemic waves and relative stability of depression. Women had a greater probability of having depression, anxiety, or stress than men in each survey (P< 0.001). The youngest group (aged 18-24) reported a higher probability (P < 0.05) of having depression, anxiety, or stress than the older groups in S1 and S2. Middle-aged people (25-59) had a greater probability of being a case in the DASS-21 scales than the oldest group (60+), except for depression in men (P = 0.179). In S3, the trend changed: the youngest group showed a decrease in depression and stress while the oldest group showed a dramatic increase (anxiety: men = 664.5%, women = 273.52%; stress: men = 786%, women= 431.37%). Conclusions: It is plausible to conclude that COVID-19 psychological fatigue exists, especially in middle-aged and older adults. Strategies to assist people who have fewer coping skills should be implemented in the near future.