Emotional memory in pregnant women at risk for postpartum depression.

Postpartum depression (PPD) is associated with debilitating effects on mothers and their infants. A previous history of depression is considered the strongest risk factor for PPD. Depressed individuals recall more negative than positive content and higher levels of stress hormones released during encoding are associated with enhanced recall of emotional stimuli. This study examined the impact of a previous history of major depressive disorder (MDD) and pregnancy on emotional memory. Seventy-seven participants completed the study [44 pregnant women in the second trimester of pregnancy with and without a lifetime history of MDD and 33 non-pregnant women with and without a lifetime history of MDD]. All completed an encoding task and provided salivary cortisol (sCORT) and alpha-amylase (sAA) samples. Participants returned one week later for a surprise incidental recognition memory task. Women with a history of MDD had worse recognition than women without a history of MDD for negative, but not positive images; this effect was independent of sCORT and sAA levels. Pregnancy did not affect emotional memory. Considering that several previous studies found enhanced memory bias for negative content during depressive states, our results suggest that clinical remission may be associated with an opposite cognitive processing of negative emotional content.