Panic Disorder: When estrogen is low, cortisol rises, raising blood pressure & blood sugar. Estrogen also affects serotonin, a brain chemical responsible for happy, balanced moods. The drop of serotonin that comes with low estrogen causes unstable moods, and as a result, anxiety. Progesterone has been shown to have a calming, soothing affect on the brain, so low levels of progesterone in combination with the hormonal changes described above can cause panic disorder as well.
