Emotion habituation is accelerated in chronic mild traumatic brain injury.

Primary Objective: Risk for mental health disturbances (e.g., depression and anxiety), is elevated following a mild traumatic brain injury (mTBI), even in the chronic stages of injury. In our previous work, we found individuals with chronic mTBI have decreased emotion habituation. The objective of the current study was to test whether reduced habituation is a mechanism underlying increased risk for mental health disturbances following mTBI. Research Design: We used a cross-sectional assessment of emotion habituation in a sample of young adults at least 1 year after an mTBI. Methods and Procedures: We repeatedly showed mTBI and control participants the same set of highly arousing, negative images and positive images. Participants rated each image for arousal and valence. Main Outcomes and Results: Unexpectedly, we found individuals with mTBI habituated faster to emotional images than controls. However, enhanced habituation was not linkd with emotional outcomes. Participants with mTBI did not differ from controls for reactivity, but blunted reactivity in all participants was associated with higher depressive symptoms. Conclusions: Although there are subtle differences in emotion responses in chronic mTBI, the differences were not associated with mental health disturbances. Nevertheless, this difference in emotional processing may increase risk for untested mental health issues.