Background: Depression and multimorbidity are common in the elderly. Assessing depression might be difficult because of the overlap of depressive and somatic symptoms, possibly leading to confounded results.
Methods: This study investigates the frequency of depression, multimorbidity and their association, the potential impact of multimorbidity on the assessment of depression by the Patient Health Questionnaire, and whether using a cut point might cause misleading results in the elderly German population (60–85 years, n= 1659).
Results: Depressive syndromes are significantly more frequent in multimorbid respondents. Multimorbidity is associated with higher item scores, especially in the somatic items, and multimorbid respondents show higher depression severity levels in comparison to non-multimorbid persons.
Conclusion: There are associations between multimorbidity and depressive symptoms, therefore potentially confounding prevalence rates. As such, causal pathways of these associations should be studied under a longitudinal perspective in future studies.