Autobiographical memory and the affective impact of positive memory recall in depressive disorders

摘要

This research program examined the role of autobiographical memory in depression and its recurrence. Despite empirical advances in the area, the cognitive processes that contribute to depressive recurrence remain poorly understood. Accordingly, Studies 1 and 2 compared features of cued memories in never-depressed and depression vulnerable (i.e., recovered depressed) individuals following a sad or neutral mood induction. In both studies, negative memories did not differ but interestingly, recovered depressed individuals recalled less vivid positive memories than their never-depressed counterparts, but only in a sad mood. Study 3 extended this line of enquiry to self-defining memories and found that some memory characteristics (i.e., reduced emotional intensity of positive memories) distinguished recovered from never-depressed groups, but only in a sad mood. That these differences emerge even when formerly depressed individuals are in remission suggests that the phenomenological characteristics of personal memories may be an important factor in vulnerability to depression. Building on these findings, the remaining experiments focused explicitly on the affective consequences that follow positive memory recall. Existing research has shown that while healthy individuals experience emotional benefits following the recall of positive memories, depressed and recovered depressed individuals do not. To examine whether this could be due to ruminative processes, Studies 4 and 5 investigated the effect of manipulating ruminative processing mode on the affective impact of recalling positive memories. The findings of Study 4 indicated that for both depressed and formerly depressed participants, concrete processing of a positive memory led to improved mood, while abstract processing did not. Taking a translational approach, Study 6 examined a brief experimenter-delivered processing mode manipulation and found that regardless of the processing mode adopted, recovered but not currently depressed individuals experienced improved mood after recalling a positive self-defining memory. This illustrates that memory type, depressive status, and processing mode all have implications for the emotional impact of recalling positive memories. In summary, the studies reported in this thesis support the idea that depression is associated with a deficit in the processing of positive material and suggest that explicitly targeting autobiographical memory characteristics and processes may improve existing treatments for depressive disorders.