Based on the evidence that the mammalian neuropeptide oxytocin (OT), best known for its role in lactation and parturition, plays a seminal role in social affiliation, emotion regulation, attachment, maternal behavior, trust, and protection against stress; and because OT neural pathways and receptors are prominently expressed in brain regions involved in emotion regulation and maternal/affiliative behavior; the study will: 1) use intranasal OT administration as a probe to assess whether it modifies activation of brain regions involved in emotion regulation in response to an emotional processing task; and 2) whether daily intranasal OT administration during the premenstrual phase improves symptoms in women with PMDD with or without a history of ELA.