Amygdala

The amygdala, responsible for processing stress, fear, and emotional responses, contains the highest density of estrogen receptors of any brain region. High estrogen is linked to anxiety, worry, and doom-and-gloom mental states by over-activating the amygdala into a heightened threat-response mode. Thiamine deficiency impairs amygdala regulation, producing exaggerated or unprovoked fear signals. In the initial response to panic symptoms, the emotional center of the brain dominates. The direction of estrogen change — not just the absolute level — determines whether mood disturbance presents as depression or anxiety, because the amygdala responds to whichever hormonal state is present. The back part of the brain is where emotional feelings originate. Low estrogen is linked to depression, occurring at the start of the menstrual cycle and during menopause.