Mental health indicators in Sweden over a 12-month period during the COVID-19 pandemic

Background The ongoing COVID-19 pandemic has had an unprecedented impact on the lives of people globally and is expected to have profound effects on mental health. Yet, self-reported large-scale online surveys on mental health are still relatively uncommon. Here we aim to describe the mental health burden experienced in Sweden using baseline data of the Omtanke2020 Study. Method Self-reported baseline data collected over a 12-month period (June 9, 2020-June 8, 2021) from the longitudinal online survey of the Omtanke2020 Study including 27,950 adults in Sweden. Participants were volunteers or actively recruited through existing cohorts and after providing informed consent responded to monthly online questionnaires on socio-demographics, mental and physical health, COVID-19 infection, and impact. Poisson regression was fitted to assess the relative risk of high mental health burden (depression, anxiety, and COVID-19 specific PTSD). Result The overall proportion of persons with high level of symptoms was 15.6%, 9.5% and 24.5% for depression, anxiety, and COVID-19 specific PTSD, respectively. Overall, 43.4% of the participants had significant, clinically relevant symptoms for at least one mental health outcome and 7.3% had significant symptoms for all three outcomes. We also observed differences in the prevalence of these symptoms across strata of sex, age, recruitment type, COVID-19 status, region, and seasonality. Conclusion While the proportion of persons with high mental health burden remains higher than in pre-pandemic publications, our estimates are lower than previously reported levels of depression, anxiety, and PTSD during the pandemic in Sweden and elsewhere.