Neural responses to induced emotion and response to social threat in intermittent explosive disorder

Abstract

Background: Individuals with intermittent explosive disorder (IED) are reported to exhibit amygdala (AMYG) hyper-activation to anger faces during functional magnetic resonance imaging (fMRI). However, it remains unknown if emotional experience is different in study participants with IED compared with healthy controls (HC). Thus, we examined the comparative effect of pleasant and unpleasant IAPS pictures in IED and HC individuals.

Method: Eighty study participants (40 IED and 40 HC) underwent fMRI scanning while viewing blocks of angry and happy faces and while viewing blocks of pleasant and unpleasant pictures from the International Affective Picture System (IAPS).

Results: Compared with HC participants, IED participants exhibited greater AMYG responses to angry, but not happy, faces; IED and HC participants, however, did not differ in AMYG responses to pleasant or unpleasant IAPS pictures. There were no group differences in Orbital-Frontal Cortical (OFC) responses to emotional faces or IAPS pictures other than a significantly higher OFC response pleasant, compared with unpleasant, IAPS pictures.

Conclusion: These findings suggest that, compared with healthy individuals, those with IED have a hypersensitive amygdala to social-emotional threat but that this characteristic does not extend to neural responses related to the experience of emotion in the context of the paradigms tested.

Keywords: Aggression; Amygdala; Intermittent explosive disorder; OFC; fMRI.