Minor depressive symptoms are associated with reduced memory performance across the adult lifespan

Individuals with a diagnosis of major depressive disorder exhibit cognitive difficulties. However, the effects of subclinical or subthreshold depressive symptoms on cognition are less known. The aim of the present cross-sectional study was to determine the possible influence of minor depressive symptoms on working memory and episodic memory. Depressive symptoms were assessed with the Beck Depression Inventory. Working memory was examined in a sample of 1662 participants, and episodic memory was examined in a subsample of 1557 individuals. All the subjects were healthy adults between the ages of 21 and 80 years. All the memory tasks were computerized. Working memory was assessed in the spatial and verbal domains at two levels of difficulty. With respect to episodic memory, we evaluated recognition and recollection. Hierarchical regression models demonstrated that depressive symptoms predicted lower memory performance in all tasks and processes after controlling for age, sex, years of education, vocabulary scores, and Mini-Mental State Examination scores. Minor depressive symptoms are powerful enough to be negatively associated with working and episodic memory performance, and stronger associations were observed as depressive symptoms worsen, indicating that their association is proportional to their number and intensity. Both types of memory are essential for performing everyday activities and preserving autonomy.