Motivational and emotional influences on cognitive control in depression: A pupillometry study

Depressed people perform poorly on cognitive tasks; however, under certain conditions they show intact cognitive performance, with physiological reactivity consistent with needing to recruit additional cognitive control. We hypothesized that this apparent compensation is driven by the presence of affective processes (e.g., state anxiety), which in turn are moderated by the depressed individual's motivational state. Clarifying these processes may help researchers identify targets for treatment that if addressed may improve depressed patients' cognitive functioning. To test this hypothesis, 36 participants with unipolar depression and 36 never-depressed controls completed a problem-solving task that was modified to elicit anxiety. The participants completed measures of motivation, anxiety, sadness, and rumination, while pupillary responses were continuously measured during problem-solving, as an index of cognitive control. Anxiety increased throughout the task for all participants, whereas both sadness and rumination were decreased during the task. In addition, anxiety more strongly affected planning accuracy in depressed participants than in controls, regardless of the participants' levels of motivation. In contrast, differential effects of anxiety on pupillary responses were observed as a function of depressed participants' levels of motivation. Consistent with the behavioral results, less-motivated and anxious depressed participants demonstrated smaller pupillary responses, whereas more highly motivated and anxious depressed participants demonstrated larger pupillary responses than did controls. Strong effects of sadness and rumination on cognitive control in depression were not observed. Thus, we conclude that anxiety inhibits the recruitment of cognitive control in depression and that a depressed individual's motivational state determines, in part, whether he or she is able to compensate by recruiting additional cognitive control.