Cohort Profile: COVIDMENT: COVID-19 cohorts on mental health across six nations

Key features • COVIDMENT [www.covidment.is] is a NordForsk-funded research collaboration across six nations, with the overarching aim to significantly advance current knowledge on mental morbidity trajectories associated with the coronavirus disease 2019 (COVID-19) in the general population and in specific risk groups. • From March 2020 through August 2021, 392 817 individuals have been recruited to the seven COVIDMENT cohorts: the Danish Blood Donor Study (N ¼ 71 562), the Estonian Biobank COVID-19 and Mental Health Data Collection cohorts (N ¼ 13 329 and N ¼ 86 116, respectively), the Icelandic COVID-19 National Resilience Cohort (N ¼ 22 849), the Norwegian BRY.DEG2020 (N ¼ 19 343), the Norwegian Mother, Father and Child Cohort Study (N ¼ 132 486), the Scottish Generation Scotland/CovidLife (N ¼ 18 518) and the Swedish Omtanke2020 (N ¼ 28 614). Semi-harmonized questionnaire data have been collected across all COVIDMENT cohorts with longitudinal data available, e.g. through linkage to the national registers. • The average age of participants ranged from 31.8 to 58.5 years across cohorts. The prevalence of depressive symptoms above cut-off point varied considerably across cohorts (4.2–20.8%). The prevalence of depressive symptoms was highest at COVID-19 incidence of 30 cases per week per 100 000 persons, i.e. 14.3% [95% confidence interval (CI): 9.4–21.8%], which was 61.0% (95% CI: 34.0–94.1%) higher than the prevalence at COVID-19 incidence of 0 cases per week per 100 000 persons (P ¼ 1.1 x 10 ^( 6)). •