We plan to enroll 60 healthy, non-pregnant premenopausal women age 18-45 who do not have hot flashes (in order to have 30 women complete all study procedures) in a trial investigating the impact of hot flashes developed in response to an injection of a GnRH agonist, leuprolide (brand name: Lupron) on sleep disruption and mood. This study is designed to mimic the menopause transition. Based on previous studies, we expect that 2/3 of the women will develop hot flashes, naturally dividing participants into two groups: + hot flashes and no hot flashes. We will collect data on sleep disruption and mood changes to compare differences between the + hot flashes group and the group of women who do not develop hot flashes on leuprolide.