532. The Role of Estradiol in Modifying Circadian Rhythms, Sleep Regularity and Risk for Depression During the Pubertal Transition

The pubertal transition (PT) is characterized by dramatic reproductive hormone fluctuations, a developmental circadian delay, and significant changes in sleep and wake patterns. The PT also marks an abrupt divergence between the sexes in risk for depression and sleep disorders that remains elevated for females across the reproductive lifespan, implicating ovarian hormones (i.e., estradiol (E2)) as a common pathway of risk. Notably, inconsistent schedules during the COVID-19 pandemic have contributed to greater sleep irregularity (especially for adolescents), which is associated with affective impairment and inferior clinical outcomes. The objective of this research is to characterize the pathophysiological impact of E2 on sleep disturbances, endocrine rhythm dysregulation and depressive symptoms in peripubertal females.