Exposure-based treatments for PTSD (48
) have the strongest empirical support and involve repeated imaginal and in vivo exposure to trauma-related stimuli. In order for exposure-based treatments to be successful, patients must be able to fully emotionally engage with the trauma-related information. Typically, patients are asked to recall details of their traumatic experience while describing them in the present tense. Exposures are designed to overcome avoidance of such stimuli by providing a safe context in which patients can fully engage with both trauma-related and “corrective” (safety) information. In this way, exposure treatment is designed to overcome and reduce avoidance symptoms, enhance affect management, and facilitate cognitive restructuring of trauma-related memories. In turn, this should bring about the reduction of reexperiencing and hyperarousal symptoms, and, ultimately, elimination of the disorder itself (49
However, exposure treatments should be used with caution in patients with significant emotional overmodulation, such as dissociative and numbing symptoms. Foa and colleagues (49
) have suggested that such symptoms can prevent emotional engagement with trauma-related information and thereby reduce treatment effectiveness (50
). In fact, a recent study (51
) suggests that levels of dissociation are an important negative predictor of psychotherapy outcome in patients with borderline personality disorder, a disorder that has often been associated with childhood abuse (52
). Also, dissociative symptoms block emotional learning in a classical conditioning paradigm (53
). Specifically, it has been shown that patients with borderline personality disorder and high levels of dissociation did not show differences in skin conductance and arousal between conditioned stimuli that were paired with an aversive sound and unpaired conditioned stimuli during acquisition and early extinction, while borderline patients with low levels of dissociation and healthy subjects did. These results suggest that emotional, amygdala-based learning processes appear to be inhibited by state dissociation through alteration of acquisition and extinction processes. Therefore, it is crucial, before commencing exposure-based treatments, to assess levels of dissociative psychopathology and provide interventions to reduce dissociative symptomatic responses to trauma-related stimuli. Failure to do so can lead to an actual increase in PTSD and related symptoms, including dissociation, emotion dysregulation, and an increase in the patient's overall distress and functional impairment.
In recognition of such dissociative complexity of symptoms of patients with chronic PTSD related to childhood abuse, Cloitre and colleagues (54
) developed an integrative and empirically supported “phase-based” intervention for long-term, child-abuse-related PTSD. Their model accounts for the significant dissociative symptoms frequently associated with repeated childhood maltreatment. Their approach delivers a stage-oriented model that uses skills training in emotion regulation. Before engaging in exposure-based therapy, Cloitre et al. (54
) provide data to support the idea that patients must develop mood regulation and grounding skills, identify and modify disordered attachment schemas learned in childhood, and work on competence in social interactions. Future treatment outcome research will need to focus on complex childhood abuse-related PTSD and other types of PTSD that have shown to have considerable dissociative symptoms (e.g., combat-related PTSD [3, 15]). This will help recognize and further develop interventions that are most effective in managing dissociative symptoms and allow them to be optimally timed in a phase-oriented treatment model.
In terms of research, the results described in this review suggest that careful attention must be paid to the differential responses of under- and overmodulation of affect often observed in PTSD. Grouping all PTSD patients, regardless of their different symptom patterns, in the same diagnostic category will hinder our understanding of posttraumatic psychopathology (19
). Classification of different PTSD subtypes will enable a more careful analysis of differential responses to psychological trauma and eventually lead to a more sophisticated understanding of the neurobiology and treatment of PTSD.
Future neurobiological research will have to closely examine the relationship between the medial prefrontal and amygdala circuitry during states of under- and overmodulation of affect and brain activation of other brain regions previously proposed as implicated in dissociative PTSD, including the thalamus, superior colliculus, and periaqueductal gray as well as brain stem structures (7
). The latter will allow a more detailed understanding of the association between higher and lower brain structures during reexperiencing and dissociative states in this disorder.