Prevalence and determinants of probable depression and anxiety during the COVID-19 pandemic in seven countries: Longitudinal evidence from the European COvid Survey (ECOS)

•Prevalence of depression and anxiety during the pandemic in European countries.•Wave 4 (wave 5; wave 6): 26.6% (25.5%; 23.8%) had probable depression.•Wave 4 (wave 5; wave 6): 25.7% (23.6%; 22.1%) had probable anxiety.•Depression: linked to higher age, great income difficulties and low quality of life.•Anxiety: linked to income difficulties and low quality of life. Our aim was to present data on the prevalence of probable depression and anxiety and to determine their correlates during the COVID-19 pandemic in seven European countries using a longitudinal approach. Longitudinal data (wave 4 in November 2020: n = 7,115; wave 5 in January 2021: n = 7,068; wave 6 in April 2021: n = 7,204) were taken from the European COvid Survey (ECOS), a representative sample of non-institutionalized inhabitants from Germany, United Kingdom, Denmark, Netherlands, France, Portugal and Italy aged 18+. Probable depression and anxiety were quantified using the established and validated PHQ-4 (2-item depression scale, PHQ-2 / 2-item anxiety scale, GAD-2). In wave 4 (wave 5; wave 6), 26.6% (25.5%; 23.8%) of all respondents had probable depression and 25.7% (23.6%; 22.1%) had probable anxiety. Prevalence rates for probable depression and probable anxiety differed significantly between countries. Among all countries and waves, particularly high prevalence rates were found among individuals aged 18 to 29 years. Longitudinal analysis showed that the likelihood of probable depression was positively associated with increasing age, great income difficulties and lower health-related quality of life. The likelihood of probable anxiety was positively associated with income difficulties, and lower health-related quality of life. Screening tool was used to quantify the outcomes. The magnitude of probable depression and anxiety during the COVID-19 pandemic in European countries was highlighted. Moreover, determining the factors associated with probable depression or anxiety (e.g., income difficulties, worse health-related quality of life) may assist in identifying individuals at increased risk.