However, those who develop C-PTSD do so as a result of the intensity of the traumatic bond – in which someone becomes tightly biolo-chemically bound to someone who abuses them and the responses they learned to survive, navigate and deal with the abuse they suffered then become automatic responses, imbedded in their personality over the years of trauma – a normal reaction to an abnormal situation. Treatment
While standard evidence-based treatments may be effective for treating post traumatic stress disorder, treating complex PTSD often involves addressing interpersonal relational difficulties and a different set of symptoms which make it more challenging to treat. According to the United States Department of Veteran Affairs:

 
The current PTSD diagnosis often does not fully capture the severe psychological harm that occurs with prolonged, repeated trauma. People who experience chronic trauma often report additional symptoms alongside formal PTSD symptoms, such as changes in their self-concept and the way they adapt to stressful events. The utility of PTSD-derived psychotherapies for assisting children with C-PTSD is uncertain. This area of diagnosis and treatment calls for caution in use of the category C-PTSD. Dr. Julian Ford and Dr. Bessel van der Kolk have suggested that C-PTSD may not be as useful a category for diagnosis and treatment of children as a proposed category of developmental trauma disorder (DTD).
This symptom is neither included in the diagnosis of dissociative disorder nor in that of PTSD in the current DSM-5 (2013). Individuals with Complex PTSD also demonstrate lasting personality disturbances with a significant risk of revictimization.Six clusters of symptoms have been suggested for diagnosis of C-PTSD:
Alterations in regulation of affect and impulses
Alterations in attention or consciousness
Alterations in self-perception
Alterations in relations with others
Somatization
Alterations in systems of meaningExperiences in these areas may include:: 199–122 
Changes in emotional regulation, including experiences such as persistent dysphoria, chronic suicidal preoccupation, self-injury, explosive or extremely inhibited anger (may alternate), and compulsive or extremely inhibited sexuality (may alternate). Variations in consciousness, such as amnesia or improved recall for traumatic events, episodes of dissociation, depersonalization/derealization, and reliving experiences (either in the form of intrusive PTSD symptoms or in ruminative preoccupation). Changes in self-perception, such as a sense of helplessness or paralysis of initiative, shame, guilt and self-blame, a sense of defilement or stigma, and a sense of being completely different from other human beings (may include a sense of specialness, utter aloneness, a belief that no other person can understand, or a feeling of nonhuman identity). Varied changes in perception of the perpetrators, such as a preoccupation with the relationship with a perpetrator (including a preoccupation with revenge), an unrealistic attribution of total power to a perpetrator (though the individuals assessment may be more realistic than the clinicians), idealization or paradoxical gratitude, a sense of a special or supernatural relationship with a perpetrator, and acceptance of a perpetrators belief system or rationalizations.