This chapter suggests that a developmental psycho-neurobiological perspective can deepen our understanding of the deficits of mind and body seen in chronic posttraumatic stress disorder. It outlines how early physical abuse and relational trauma induce central and autonomic hyperarousal, the latter associated with severe states of bodily dysregulation and subjective pain. The principle that the early events of development have far-reaching and long-enduring effects is one of the very few elemental and overarching postulates that is shared by all disciplines studying living organisms. Reunion microinteractions are critical moments of early object relations involving emotional reconnection after separations, specifically reentering into patterned affective transactions with the object. Hypocortisolism develops subsequent to extended periods of elevated cortisol in response to trauma, and adverse conditions in early life that induce elevated levels of cortisol are now proposed to contribute to the development of hypocortisolism in adulthood.