survival. The five traditional signals (sight, hearing, taste, smell, and touch) contribute to the developing brain structure and its function. Infants and children begin to create internal representations of their external environment, and in particular, key attachment relationships, shortly after birth. Violent and victimizing attachment figures impact infants' and young children's internal representations. The more frequently a specific pattern of brain neurons is activated, the more permanent the internal representation associated with the pattern becomes. This causes sensitization in the brain towards the specific neural network. Because of this sensitization, the neural pattern can be activated by decreasingly less external stimuli. Childhood abuse tends to have the most complications with long-term effects out of all forms of trauma because it occurs during the most sensitive and critical stages of psychological development. It could also lead to violent behavior, possibly as extreme as serial murder. For example, Hickey's Trauma-Control Model suggests that "childhood trauma for serial murderers may serve as a triggering mechanism resulting in an individual's inability to cope with the stress of certain events." Often, psychological aspects of trauma are overlooked even by health professionals: "If clinicians fail to look through a trauma lens and to conceptualize client problems as related possibly to current or past trauma, they may fail to see that trauma victims, young and old, organize much of their lives around repetitive patterns of reliving and warding off traumatic memories, reminders, and affects." Biopsychosocial models offer a broader view of health problems than biomedical models. Effects Evidence suggests that a minority of people who experience severe trauma in adulthood will experience enduring personality change. Personality changes include guilt, distrust, impulsiveness, aggression, avoidance, obsessive behaviour, emotional numbness, loss of interest, hopelessness and altered self-perception. Treatment A number of psychotherapy approaches have been designed with the treatment of trauma in mind—EMDR, progressive counting (PC), somatic experiencing, biofeedback, Internal Family Systems Therapy, and sensorimotor psychotherapy, and Emotional Freedom Technique (EFT) etc. Trauma -and violence-informed care provides a framework for any person in any discipline or context to promote healing, or at least not re-traumatizing. There is a large body of empirical support for the use of cognitive behavioral therapy for the treatment of trauma-related symptoms, including post-traumatic stress disorder. Institute of Medicine guidelines identify cognitive behavioral therapies as the most effective treatments for PTSD. Two of these cognitive behavioral therapies, prolonged exposure and cognitive processing therapy, are being disseminated