Biased information processing as an endophenotype for depression

Cognitive theories assume a uniform processing bias across different samples, but the empirical support for this claim is rather weak and inconsistent. Therefore, coherence between biases across different cognitive domains in a sample of 133 non-depressed (Study 1) and a sample of 266 formerly depressed individuals (Study 2) was examined. In both studies, individuals were selected after a successful sad mood induction procedure. A Dot Probe task, an Emotional Stroop task and a self-referential Incidental Learning and Free Recall task were administered to all participants. Principle component analyses indicated coherence between attentional and memory bias in non depressed, while in formerly depressed individuals distinct components for attentional biases and for memory bias were uncovered. The data suggest that in formerly depressed individuals, self-referent processing during encoding may be related to memory bias, whereas in non-depressed individuals memory bias may be related to both attentional bias and self-referent processing.