Memory for novel positive information in major depressive disorder

Major depressive disorder (MDD) is associated with biases in memory, including poor memory for positive stimuli. It is unclear, however, if this impaired memory for positive stimuli in MDD is related to difficulties in the initial processing of stimuli, or alternatively, reflects a decreased ability to draw on memories of positive stimuli after they have been formed. Using two versions of a word-matching task that featured a mixture of novel and practiced emotionally valenced words, we found that depressed individuals experienced greater difficulty learning positively valenced information than did their nondepressed peers. This difficulty seemed to be specific to initial encounters with the novel, but not the practiced, positive stimuli. These findings suggest that memory deficits for positive information associated with depression are related to how this information is initially processed. Implications of these findings for interventions are discussed and directions for future research are advanced.