According to information processing theories of emotional disorders, memory processes play an important role in the etiology and maintenance of depression. Indeed, depressed patients often exhibit both a general memory impairment and a mood-congruent memory bias, such that their memory performance is generally poor, except for self-related, negative information. These two phenomena were investigated in the studies reported here.
In Experiment 1, 36 severely depressed inpatients and 36 healthy controls participated. After incidental learning of depression-related, neutral and positive words, explicit memory for the words was assessed with a free recall task, and implicit memory was assessed with an anagram solution task. Results showed that depressed and controls differed in explicit memory performance, while implicit memory performance was unaffected. In addition, severely depressed patients showed a mood-congruent memory bias in implicit memory, but not in explicit memory. In Experiment 2, 27 women with major depression, 35 women with generalized social phobia, and 55 healthy controls participated in the same tests as in Experiment 1. The depressed participants showed clear evidence of explicit and implicit memory biases for depression- related words.
The implications of these results for competing theories of cognitive processing in emotional disorders are discussed.