Schizophrenia is not just a “cognitive” illness; patients also suffer from disturbances in emotional processing and in their reactions to stressful events. Research on emotion and stress in schizophrenia has tended to proceed independently of research on cognition. Nonetheless, there are intriguing hints that important cognitive effects may occur in patients when they are challenged with emotionally salient or stressful stimuli. This is not surprising, given that the dopamine system has been implicated in the stress response, as well as in cognitive functioning.
One hypothesis is that cognitive functioning in schizophrenia patients is particularly susceptible to disruption by emotionally challenging or stressful situations due to an already vulnerable dopamine system. Consistent with this hypothesis, in work recently completed by Deanna Barch and graduate student Jennifer Burbridge we have found that individuals with schizophrenia produce more disturbed speech in response to questions designed to elicit an emotional response as compared to questions designed to elicit a neutral response (Burbridge & Barch, in preparation) .
In addition, in healthy subjects we have found that the emotional content of stimuli such as words and faces influences the ease with which they are maintained in WM. However, it is not clear what specific mechanisms underlie these influences of emotion on cognitive processing. A number of different explanations are possible including: 1) an influence of arousal on cognition; 2) an influence of stress on dopamine function and cognition; and/or 3) overlap in the brain regions that mediate at least certain types of emotional and cognitive processing. Thus, to examine these different hypotheses, we are conducting a series of studies in both healthy controls and patients designed to examine the influence of emotion and stress challenges on cognitive function.
In work with two undergraduate students enrolled in the Hewlett Mind/Brain program, we are examining the influence of a brief stress manipulation on performance in both a standard and an emotional Stroop task. In conjunction with Jennifer Lofton, an undergraduate honor’s student, we are examining memory for emotional and non-emotional words in patients with schizophrenia. In addition, the focus of Jennifer Burbridge’s Masters thesis will be to directly examine indices of arousal and cortisol release during paradigms that manipulate emoitional influence on cognitive processing.