Depression In Patients With Implicit Memory, Self-reference Study

Implicit biases for negative information may be important maintenance mechanism in depression, which was not completely supported by the past researches. There are no researches as to the relationship between implicit memory biases and self-reference in depression. With the process dissociation procedure in this current study, three studies were conducted to test the implicit biases for negative information and their association with self-reference in depression.In study one, 24 depressed people and 24 normal controls were enrolled; 180 emotional valence words (60 positive, 60 neutral and 60 negative words) were selected as experimental materials; semantic processing, recognition test, self-reference, recall test, and Beck Depression Inventory (BDI) were sequentially administered on the computer in terms of the experimental procedure. The study results indicated that depressed people remembered more negative emotional words than the normal controls, while the normal controls remembered more positive emotional words than the depressed people. The depressed people showed more negative biases in their self reference than the normal controls, the normal controls showed more positive biases in their self-reference than the depressed people. Both conscious and unconscious memories were not significantly associated with their self-reference.In study two, 24 depressed people and 24 normal controls were enrolled; 180 emotional valence words are the same as study one's; self-reference, recognition test, semantic processing, recall test, and Beck Depression Inventory (BDI) were sequentially administered on the computer in terms of the experimental procedure. The results revealed that the main effect of diagnosis achieved statistical significance in conscious memory, depressed people showed biases not only for negative but positive information. In unconscious memory, there were significant interaction between diagnosis and emotional valence. Depressed people showed more negative biases in their self reference than the normal controls, the normal controls showed more positive biases in their self-reference. Both conscious and unconscious memories were not significantly associated with their self-reference.In study three, Multi-ANOVA on conscious memory demonstrated that the main effect of diagnosis, F=10.935, p<0.01, achieved statistical significance. The main effect of materials, F=3.861, p<0.05, also achieved statistical significance. Other main effects or interactions showed no statistical significance. Similarly multi-ANOVA on unconscious memory revealed that the main effect of diagnosis, F=5.484, p<0.01, achieved statistical significance. Other main effects or interactions showed no statistical significance. The results of three studies indicate that explicit memory and implicit memory of depressed people have different characteristics. In explicit memory, depressed people show biases for both positive and negative information, and the biases are associated with their self-reference. In other words, there are self reference effects of explicit memory in depression. In implicit memory, depressed people show biases for negative information, and the biases are not associated with their self-reference. In other words, there are no self reference effects of implicit memory in depression.The results suggest the net model and the schema model of emotion and memory in depression be integrated. Depressed people apply not only the net model but also the schema model to information processing. Which model depressed people choose depends on their processing strategy.