Abstract: Abstract Depression affects 340 million people around the world. It has become one of the major cause of death and disability. Depression occurs in women about twice as in men ,which suggest that estrogen may play a role .Many researches have shown that E2 in plasma is significantly lower in women with depression than those with no depression and increased after treatment .But there is few research on men about that. Efficacy of estrogen for the treatment of depression is positive in some research. But the mechanism is to be further probed. The side effect of estrogen has restricted its clinical use. Further research might gain more meaningful result.

Key words: Depression, Estrogen, Estrogen receptor