Multimorbidity and Mental Health Trajectories Among Middle-Aged and Older US Adults During the COVID-19 Pandemic: Longitudinal Findings From the COVID-19 Coping Study

Background and Objectives This study aimed to examine the associations between multimorbidity at the COVID-19 pandemic onset and subsequent longitudinal trajectories of depressive symptoms, anxiety symptoms, and loneliness in middle-aged and older adults over a 12-month follow-up. Research Design and Methods Data were from monthly online questionnaires in the COVID-19 Coping Study of U.S. adults aged >= 55 from April/May 2020 through April/May 2021 (N = 4,024). Multimorbidity was defined as having >= 2 versus <2 chronic conditions at baseline. Mental health outcomes were assessed monthly as depressive symptoms (8-item Center for Epidemiologic Studies Depression scale), anxiety symptoms (5-item Beck Anxiety Inventory), and loneliness (3-item UCLA Loneliness Scale). We used multivariable-adjusted population- and attrition-weighted mixed-effects linear models to examine the longitudinal associations between multimorbidity and mental health symptoms. Results Multimorbidity at the pandemic onset was associated with elevated depressive (b = 0.37; 95% CI: 0.16-0.59) and anxiety (b = 0.39; 95% CI: 0.15-0.62) symptoms at baseline. Changes in symptoms for all three mental health outcomes were nonlinear over time, with worsening symptoms over the first 6 months of the pandemic (April/May to September/October 2020), followed by improvement in symptoms over the subsequent 6 months (September/October 2020 to April/May 2021). Middle-aged and older adults with multimorbidity experienced faster rates of change in anxiety symptoms and loneliness than those without multimorbidity, with persistently elevated mental health symptomatology throughout the follow-up. Discussion and Implications Results highlight the unique and persistent mental health risks experienced by middle-aged and older adults with multimorbidity during the COVID-19 pandemic. The observed improvements in symptoms underscore the mental resilience of these individuals, indicating their adaptation to the ongoing pandemic.