Background: There are numerous indications that impaired inhibition of negative affective material could be an important cognitive component of depression. To study whether impaired inhibition of negative affect is a cognitive vulnerability factor explaining (recurrent) depression, inhibition of positive and negative affective stimuli was examined in hospitalized depressed patients, formerly depressed individuals and never-depressed controls.
Methods: To investigate inhibitory dysfunctions in the processing of emotional material, we used an affective modification of the negative priming task with pictures of sad and happy facial expressions.
Results: Compared to never-depressed controls, depressed patients showed a specific failure to inhibit negative information, whereas inhibition function for positive material was unaffected. Surprisingly, formerly depressed individuals demonstrated impaired inhibition of negative and positive information.
Limitations: Because of the significant correlations between depression and anxiety self-report scores, the observed reduced inhibitory effect toward negative material in the depression group cannot strictly be attributed as depression-specific.
Conclusions: In accordance with our hypothesis, strongly impaired inhibition of negative affect was found in depressed patients. Based on the present findings, we argue that impaired inhibition of negative affect could be an important construct in cognitive theories on depression linking cognitive biases to neuropsychological impairments in depression. The data in the formerly depressed individuals are less conclusive and several hypotheses are detailed that could explain how the absence of inhibition of affective information could relate to recurrent depression.