Amygdala Structure and Function: Association With Transdiagnostic Trauma Severity in Anxiety and Mood Disorder Patients.

Reductions in both the size of the amygdala and functional activity during emotional processing have been independently associated with trauma exposure and severity, raising the question of whether reduced volume prompts reduced functional activation. In this multimodal assessment, the relationship between amygdala structure and function was investigated in mood and anxiety patients to determine their covariation and their relationship to trauma magnitude. Overall, amygdala volume and functional emotional reactivity were unrelated, with smaller volumes and reduced emotional reactivity each independently predicting trauma magnitude for women, and mediation analysis did not support a hypothesis that the relationship between reduced functional activity and trauma severity depends on amygdala volume. Structural and functional differences were instead separately related to different facets of trauma experience, highlighting the need for longitudinal and multimodal analyses to further elucidate the relationship between brain structure, function, and psychopathology.