The Relationship Between Subjective Cognitive Decline and Objective Cognitive Performance in Older Adults With Treatment-Resistant Late-Life Depression: The Role of Depression Severity

Objectives: Examine the role of depression severity in linking subjective and objective indicators of cognitive decline. Methods: 354 participants (60+) were drawn from a multicenter longitudinal neuroimaging and neurocognitive study of TRLLD (the "OPTIMUM-NEURO" study). Subjective cognitive decline (SCD) was assessed using the everyday cognition scale. Objective cognitive performance (OCP) was assessed using the Repeatable Battery for Neuropsychological Status and subtests of the Delis-Kaplan Executive Functioning System. Depression severity was assessed using the clinician-administered Montgomery-Asberg Depression Rating Scale. Statistical analysis involved demographic-adjusted linear regression models and causal mediation analysis. Results: Participant and study partner-reported SCD were associated with OCP in a broad range of cognitive domains. Greater depression severity was related to worse SCD and OCP but did not statistically mediate any SCD-OCP relationships. Conclusions: Among individuals with TRLLD, higher SCD is related to greater depression severity; however, SCD and depression severity each independently relate to OCP.