The enduring effects of depressive thoughts on working memory

Background Depressive thoughts are known to persist in persons with depressed mood leading to rumination and exacerbation of depressive symptoms. What has not yet been examined is whether this persistence of depressive thoughts can lead to impairment of working memory (WM). Methods We assessed whether receiving a WM task featuring depressive cues could bias performance on a subsequent, non-depressive WM task for dysphoric individuals (DIs) compared to non-DIs. Results DIs showed significantly attenuated performance on the WM task with depressive cues compared to non-DIs. Further, when DIs were given the WM task with depressive cues first, they showed deficits on a second WM task without depressive cues, compared to DIs given the non-depressive WM task first and non-DIs in either condition. Limitations Unselected recruitment procedures did not permit balanced sample sizes in each group. Future research is needed to assess whether these results extend to a clinically depressed sample and whether WM deficits are the consequence of depressed mood, or a risk factor for the development and maintenance of depressed mood. Conclusions Results suggest that, for DIs, the influence of depressive cues on performance transfers to subsequent tasks in which these cues are no longer present. These results support the hypothesis that when depressive thoughts are part of depressed persons' conscious experience, cognitive deficits arise. Further, these results suggest an ecologically-relevant mechanism by which day-to-day cognitive deficits in depression can develop.