Brain Imaging Study in Menopausal Women With and Without Major Depressive Disorder

The purpose this study is to measure cortical gama-aminobutyric acid levels (GABA) levels in menopausal women with major depressive disorder and healthy subjects using nuclear magnetic resonance spectroscopy (MRS). Measurements will be compared in 1) menopausal healthy subjects before and after estrogen replacement, and after fourteen days of medroxyprogesterone administration; and 2) in depressed menopausal subjects before and after treatment of their depression with antidepressant alone, estrogen alone or antidepressant plus estrogen. Cortical GABA levels will be correlated with plasma GABA and neurosteroid levels. Neurosteroids to be measured include progesterone, allopregnanolone, pregnenolone, and pregnenolone sulfate.