Objective: Despite the possibility that cognitive deficits associated with depression may have different patterns depending on the level of neurocognitive impairment, there remains no clear evidence of this. This study aimed to investigate the differential association between depression and cognitive function in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD).
Methods: A cross-sectional analysis was performed of data from 1,724 patients with MCI and 1,247 patients with AD from the Clinical Research Center for Dementia in Korea. Depression was assessed using the Korean form of the Geriatric Depression Scale, and cognition was measured using the Seoul Neuropsychological Screening Battery, which includes five domains (attention, language and related function, visuospatial function, memory, and frontal/executive function).
Results: Significant differences were found between the two groups (non-depressed vs. depressed) in visuospatial, memory, and executive function domains in the MCI group, as well as in the attention domain in the AD group. The association between depressive symptoms and cognitive function was significantly greater in patients with MCI than in those with AD. These associations were more pronounced in memory and executive function.
Conclusion: Our findings suggest that the association between depression and decreased cognitive function is more pronounced in MCI than AD.
Keywords: Alzheimer’s disease; cognitive impairment; depression; mild cognitive impairment; neuropathology.