Estrogen-mediated effects on depression and memory formation in females

Women are twice as likely to suffer from depression as men. It has been proposed that the ovarian hormones estrogen and progesterone contribute to the higher incidence of this potentially debilitating disorder. Depression can also be accompanied by a loss of cognitive performance. Here we review estrogen-mediated effects on depression and memory formation in females. We propose that changes in levels of estrogen are associated with sex differences in learning as well as changes in affect prior to menses, immediately after pregnancy and during perimenopause and the menopausal transition. Finally, we discuss the animal model of depression known as 'learned helplessness' and describe research from our laboratory demonstrating that exposure to an acute stressful experience compromises a female's later ability to acquire certain types of new memories. This response to stressful experience is opposite to that observed in males and is dependent on the presence of estrogen, and more specifically-changing levels of estrogen. This observation indicates that females and males can use different hormonal and neural mechanisms to respond to the same emotional event and underscore the importance of studying the unique and changing biology of females, especially when considering treatment strategies for depression and stress-related illness.