Neuroendocrine Risk for PTSD in Women

The majority of Americans will experience a traumatic event during their lifetimes. However, women are twice as likely as men to experience negative psychiatric outcomes following trauma, including post-traumatic stress disorder (PTSD) and depression. The reason for the increased prevalence in women is unclear, partially because of the historical lack of investigation of females in both human and pre-clinical animal research. The researchers propose to investigate the role of sex hormones in contributing to women's risk for PTSD. The study will investigate relationships between trauma exposure and women's menstrual cycle, examining key events in the cycle, including menstruation, ovulation, and mood changes. The study will then examine relationships between the level of naturally-cycling estradiol (E2; the primary female sex hormone), and brain-based measures of stress vulnerability. This includes amygdala hyper-reactivity to threat. The trial will study if trauma-exposed women with lower E2 levels during the luteal phase will report greater PTSD symptoms, and show more stress-vulnerable patterns of brain function. It will also examine the effects of exogenous application of estrogen on PTSD symptoms. Women will begin tracking their cycle using a free and widely-used cycle-tracking smartphone app "Clue" for one full menstrual cycle. * For Study Aims 1 \& 2 (N=120): Participants will be contacted on the first day of their menstrual period in the second cycle, and scheduled for an MRI with a 4-day window (early follicular phase). Participants will be randomized to begin with either the E2 or placebo patch. The will receive an E2 or placebo patch 1 day prior to the MRI visit, with a blood draw on the morning of the MRI visit (to assess hormone levels), 1 hour prior to scanning. On the first day of the third cycle (onset of menses), women will all be scheduled for their second MRI visit. Participants will experience the opposite condition from their first MRI scan. They will receive an E2 or placebo patch 1 day prior to the MRI visit in the afternoon, with a blood draw on the morning of the MRI visit, 1 hour prior to scanning. * For Study Aim 3 (N=120): Participants will begin daily urine ovulation tests on Day 11 of their cycle, and will record the results in Clue. When participants record a positive ovulation test during the second month of cycle monitoring, they will be contacted to schedule their MRI visit 5-7 days following ovulation (during the luteal phase). The experimental protocol will otherwise be the same as in Aims 1 and 2, with participants randomized to either E2 or placebo at the first visit and returning the next month for the other condition. The scientific premise of this study is that low E2 may contribute to stress vulnerability in women. Findings may aid in the development of treatments that will enhance women's mental health outcomes following trauma.