Depression and the accessibility of memories. A longitudinal study.

A group of depressed patients and a group of normal subjects were assessed on two occasions. On each they were required to recall past real life experiences associated with a series of stimulus words. Subjects were subsequently required to rate each experience for happiness and pleasantness. The depressives showed an increased probability of recalling sad memories; within this group there was a significant relationship between severity of depressed mood and the percentage of sad memories recalled. The extent of reduction in depressed mood from occasion 1 to occasion 2 was significantly related to the increase in accessibility of happy memories and the decrease in recall of sad memories. For those patients who improved between the two occasions there was a significant reduction in the probability of recall of a very unhappy memory. The results extend the previous findings on the effect of mood state on the accessibility of memories of differing affective tone. The findings are discussed in terms of context specific encoding and retrieval.