Abstract
OBJECTIVE: Heightened amygdala reactivity to aversive stimuli in major depression is regarded as a core feature of the underlying physiology but individual differences in amygdala response may also arise secondary to persistent changes in limbic function during early neurodevelopment relative to stressors such as childhood trauma. We sought to determine whether heightened amygdala response is a core feature of depression or a general risk factor for psychopathology secondary to early life stress. METHOD: Twenty unipolar depressed patients with and without a history of significant early life trauma and 16 healthy comparison subjects underwent functional MRI in a cross-sectional study comparing neural response to sad and neutral faces. RESULTS: We observed a robust positive correlation between physical abuse and right amygdala response. A much weaker relationship with other forms of abuse and neglect was also found, suggesting differences between abuse subtypes and amygdala response. Group differences in amygdala response suggest heightened reactivity was not characteristic of persons with depression in general but was true primarily in those with a significant history of abuse. CONCLUSION: These findings suggest the relationship between childhood trauma and risk for depression is mediated by heightened amygdala response but varies by abuse type. Preliminary evidence for two distinct depression phenotypes based on trauma history was also supported, consistent with differential etiology.