Women, declining estrogen and depression

Researchers believe estrogen may have a role in the development of depression in women. Studies have shown a higher rate of depression among women during the transition into menopause, which may be related to declining levels of estrogen production. 
According to MedSource, some research suggests estrogen replacement therapy may be beneficial for postmenopausal women with mild to moderate cases of depression. However, there are some safety concerns with steroidal hormone replacement therapy (estrogen and progesterone derived from the urine of pregnant horses–taken simultaneously) as this treatment has been shown to be associated with an increased risk for breast cancer and a slightly increased risk for heart disease, stroke and pulmonary embolism. In a recent report, estrogen therapy alone was associated with a significantly increased risk for stroke. This has not been found to be the case with natural (non steroidal) estrogen.

Researchers say changes in serotonin levels may also affect cognition, memory and sleep.