Memory awareness in patients with Major Depressive Disorder

Abstract

Background: Subjective Memory Complaints (SMC) along with cognitive deficits are frequently observed in patients with Major Depressive Disorder (MDD). The relationship between SMC and objective memory performance in patients with MDD was evaluated, in comparison with patients with Mild Cognitive Impairment due to Alzheimer's Disease (MCI-AD) and healthy controls (HC).

Methods: Patients with MDD (n = 47), MCI-AD (n = 43) and HC (n = 45) were assessed with a self-report memory complaints scale (SMCS) and underwent a comprehensive clinical and neuropsychological assessment. A discrepancy score between the Logical Memory delayed recall and the SMCS total score was calculated as a measure of memory awareness.

Results: Patients with MDD (12.5 ± 4.4) and patients with MCI-AD (10.9 ± 4.1) had not significantly different SMCS total scores, whereas HC showed significantly lower scores (4.0 ± 3.0). As much as 74.5% of patients with MDD patients and 65.1% of patients with MCI-AD reported prominent memory complaints, whereas only 4.4% of HC did. Patients with MDD had relatively preserved memory tests, resulting in a higher discrepancy score than both patients with MCI-AD and HC. The SMCS total score correlated positively with depressive symptoms in the 3 groups of participants.

Conclusions: Patients with MDD showed inaccurate memory self-awareness as they under-estimated their memory functioning, a pattern distinct from both patients with MCI-AD and HC.

Keywords: Alzheimer's disease; Awareness; Major depression; Memory; Mild cognitive impairment; Subjective memory complaints.