Objectives: To expand current models of depressive symptoms in older adults with multimorbidity (MM) beyond the number of illnesses as a predictor of worsened mental health.
Methods: Two-sample replication study of adults ≥62 years old with ≥ two chronic illnesses, who completed validated questionnaires assessing depressive symptoms, and disease- and treatment-related stressors. Data were analyzed using hierarchical linear regression.
Results: The model of cumulative number of illnesses was worse at explaining variance in depressive symptoms (Sample 1 R2 = .035; Sample 2 R2 = .029), compared to models including disease- and treatment-related stressors (Sample 1 R2 = .37; Sample 2 R2 = .47). Disease-related stressors were the strongest factor associated with depressive symptoms, specifically, poor subjective cognitive function (Sample 1: b = -.202, p = .013; Sample 2: b = -.288, p < .001) and greater somatic symptoms (b = .455, p < .001; Sample 2: b = .355, p < .001).
Conclusions: Using the number of illnesses to understand depressive symptoms in MM is a limited approach. Models that move beyond descriptive relationships between MM and depressive symptoms are needed.
Clinical implications: Providers should consider the role of somatic symptom management in patients with MM and depressive symptoms.
Keywords: Aging; depressive symptoms; disease burden; multimorbidity; older adults; treatment burden.