Implicit memory bias in clinical and non-clinical depression

Abstract

Implicit memory for depression-relevant information was examined in non-clinical subjects with high versus low levels of dysphoria (Experiment 1), and in subjects who met DSM-III-R diagnostic criteria for depression versus normal controls (Experiment 2). The implicit memory test was a primed lexical decision task, with depression-relevant and neutral words, and suprathreshold and subthreshold primes. In Experiment 1, dysphoric subjects showed greater subthreshold priming of depression words than non-dysphoric subjects. In Experiment 2, clinically depressed individuals showed greater subthreshold and suprathreshold priming of depression words than normal non-depressed controls. The results confirmed those from previous studies using the primed lexical decision task to investigate implicit memory for negative information in depression (Bradley, Mogg & Williams, 1994, Behaviour Research and Therapy, 32, 65–78; Bradley, Mogg & Williams, 1995, Behaviour Research and Therapy, 33, 755–770). Implications for recent cognitive models of depression are discussed.