Previous studies suggest that there is a strong association between depression and cognitive decline, and that concurrent depressive symptoms in MCI patients could contribute to a difference in neurocognitive characteristics compared to MCI patients without depression. The authors tried to compare neurocognitive functions between MCI patients with and without depression by analyzing the results of neuropsychological tests.

Participants included 153 MCI patients. Based on the diagnosis of major depressive disorder, the participants were divided into two groups: depressed MCI (MCI/D+) versus non-depressed MCI (MCI/D−). The general cognitive and functional statuses of participants were evaluated. And a subset of various neuropsychological tests was presented to participants. Demographic and clinical data were analyzed using Student t-test or χ2 test.

A total of 153 participants were divided into two groups: 94 MCI/D+ patients and 59 MCI/D− patients. Age, sex, and years of education were not significantly different between the two groups. There were no significant differences in general cognitive status between MCI/D+ and MCI/D− patients, but MCI/D+ participants showed significantly reduced performance in the six subtests (Contrasting Program, Go-no-go task, Fist-edge-palm task, Constructional Praxis, Memory Recall, TMT-A) compared with MCI/D− patients.

There were significantly greater deficits in neurocognitive functions including verbal memory, executive function, attention/processing speed, and visual memory in MCI/D+ participants compared to MCI/D−. Once the biological mechanism is identified, distinct approaches in treatment or prevention will be determined.