This chapter begins with a synopsis of neurodevelopmental issues relevant to understanding the relationship between childhood anxiety disorders and adult PD. Characterizing the ontogeny of psychobiological alterations throughout development is potentially important for the early identification and treatment of at-risk children. Accordingly, this article attempts to build the case that there likely exist distinct genetically mediated trait markers for PD beginning in childhood that are chronic and persistent even after effective treatment and disease remission. The trait markers span the gamut of areas investigated biologically in PD, including respiratory, cardiovascular, neuroendocrine, genetic, and neuroanatomic systems.