Developmental trauma refers to the complex and pervasive exposure to life-threatening events that occur through sensitive periods of infant and child development, disrupt interpersonal attachments, compromise an individuals safety and security operations, alter foundational capacities for cognitive, behavioral, and emotional control, and often contribute to the development of complex PTSD in adulthood. It is a condition characterized by chronic and multifaceted adverse experiences during childhood, which can impact a childs mental health, emotional regulation, and interpersonal relationships. Developmental trauma is inextricably linked to disruptions in social cognition, physiological and behavioral regulation, and parent-child attachments. Children exposed to adverse childhood experiences (ACEs) and pervasive interpersonal traumas may go on to develop PTSD and, in most cases, will further undergo a significant shift in their developmental trajectory. Developmental trauma associated with early experiences of abuse or neglect leads to multi-faceted and longstanding consequences and underscores critical periods of development, complex stress-mediated adaptations, and multilevel, trans-theoretical influences in the diagnostic formulation and treatment of traumatized children, adolescents, and adults. Symptoms of developmental trauma include habitual self-harm, extreme distrust, and verbal or physical aggression towards others, putting them at risk of developing other psychiatric disorders, such as bipolar disorder and conduct disorder, later in life.