Trajectories of depression, anxiety and stress among adults during the COVID-19 pandemic in Southern Switzerland: the Corona Immunitas Ticino cohort study

OBJECTIVES: Using longitudinal data from Southern Switzerland we assessed ten-month temporal trajectories of moderate to severe depression, anxiety and stress among adults after the first pandemic wave and explored differences between sociodemographic and health status groups. STUDY DESIGN: This was a population-based prospective cohort study. METHODS: Participants were 732 (60% women) adults aged 20–64 years who completed the Depression, Anxiety and Stress Scale on a monthly base since August 2020 until May 2021, as part of the Corona Immunitas Ticino study based on a probability sample of non-institutionalized residents in Ticino, Southern Switzerland. RESULTS: Prevalence of moderate to severe depression increased from 7.5% in August 2020 to 12.5% in May 2021, anxiety increased from 4.8% to 8.1% and stress increased from 5.5% to 8.8%. A steeper increase in poor mental health was observed between October 2020 and February 2021. Men had a lower risk for anxiety (odds ratio [OR] = 0.58, 95% confidence interval [CI] = 0.36–0.95) and stress (OR = 0.61, 95% CI = 0.44–0.95) than women. Suffering from a chronic disease increased the risk for depression (OR = 1.82, 95% CI = 1.12–2.96), anxiety (OR = 2.38, 95% CI = 1.44–3.92) and stress (OR = 1.87, 95% CI = 1.14–3.08). The differences between these groups did not vary over time. CONCLUSIONS: In a representative Swiss adult sample, prevalence of moderate to severe depression, anxiety and stress almost doubled in the course of ten months following the end of the first pandemic wave in spring 2020. Women and participants with pre-existing chronic conditions were at a higher risk of poor mental health.