The introduction to reflective function in the first three chapters of this volume is followed by a sobering sketch of the disastrous developmental paths leading to severe personality disturbances. Traumatic experiences such as separation or perception of hatred from the caregiver, neglect, physical or sexual abuse, or care alternating with abuse create in infants and children increased arousal and trigger the autonomic fight-or-flight alarm system. Thus, when feeling cut off from their capacity to create an integrated representation of the caregiver and from their own coherent sense of self-agency, lacking the ability to fight or flee, infants and children will "escape" by inward flight, i.e., dissociation, and will detach threatening sensations from their other experiences, fragmenting their perceptions into nonintegrated components, and developing ultimately primitive psychological defense mechanisms such as splitting and projective identification. Biological vulnerabilities in children who are inhibited or have learning disabilities, reduced levels of D2 dopamine receptors, attention deficit hyperactivity disorder, or mood disorders significantly increase the tendency toward dissociation for two reasons. First, anger, irritability, or an unstable mood give these children a fragmented sense of themselves and of others. Second, their ever-restless and changing behavior generates or exacerbates chaos in their environment: the parents are exhausted, and their severely challenged reflective function is compromised. To deal with mounting pressures to integrate contradictory perceptions of self and of others, these children become increasingly demanding and rigid as they seek to coerce parents, siblings, peers, and teachers to mirror their ever-changing fragmented internal states in an attempt to control their interpersonal relationships and regulate their affective experiences.