Contest winner: A healthy dose of dissociation

The term dissociation, in the context of combat, has developed a negative connotation. This is in part due to the association with anxiety disorders in the “Diagnostic and Statistical Manual of Mental Disorders” (4th ed., rev.; DSM–IV–TR; American Psychiatric Association, 2000). A peritraumatic dissociative experience (i.e., dissociation during exposure to a traumatic event) is required for the diagnosis of acute stress disorder (ASD), and ASD is determined to predict future posttraumatic stress disorder (PTSD; Hansen, Armour, & Elklit , 2012). In fact, compared with other risk factors, peritraumatic dissociation was found to be the strongest predictor of PTSD (Ozer, Best, Lipsey, & Weiss , 2003). Dissociation has been studied as a predictor of subsequent PTSD in combat exposure as well. Vietnam veterans with PTSD self-reported peritraumatic dissociation more often than those without PTSD, and also scored higher on a measure of dissociative symptoms (Bremner et al., 1992). However, could dissociation in the military, particularly during combat, be adaptive as opposed to deleterious?

Defining dissociation is complicated. The DSM–IV–TR defines dissociation as disruptions and fragmentations of the usually integrated functions of consciousness, memory, identity, body awareness, and perception of the self and the environment (American Psychiatric Association, 2000). Research on dissociation frequently focuses on emotional regulation and numbing. Historically, dissociation was acknowledged as a key feature of hysteria and exposure to trauma (Freud, 1920–1922/1955). Interest in the topic of dissociation has fluctuated over time in the field of clinical psychology; however, the fifth edition of the “Diagnostic and Statistical Manual of Mental Disorders” (American Psychiatric Association, 2013) includes a new dissociative subtype of PTSD. This additional subtype is especially relevant to the evidence-based treatments available to veterans and service members.

During acquisition and early extinction in exposure-based therapies, individuals with dissociation do not exhibit the same change in skin conductance or arousal that is typical during treatment for PTSD (Lanius, Brand, Vermetten, Frewen, & Spiegel , 2012). This deviation supports the theory that PTSD and the dissociative subtype differ in “emotional modulation” (Lanius et al., 2010). The hyperarousal and reexperiencing symptoms in the DSM–IV–TR diagnosis of PTSD involve emotional under modulation, whereas the derealization and depersonalization symptoms of the dissociative subtype involve emotional over modulation. This “numbing” phenomenon in the overmodulation of emotions suggests that dissociation could be a regulatory strategy to ameliorate intense hyperarousal during combat and, therefore, protective.

Since intense emotion can detract from a soldier's ability to engage in the appropriate occupational response, emotional overmodulation that occurs during peritraumatic dissociation could help the service member engage more effectively in combat. Horowitz (1986) proposed that peritraumatic dissociation could limit the encoding of a threatening experience and, therefore, serves a protective function. When overmodulation continues to occur, however, the dissociation could have clinical implications.

Persistent dissociation is the prolonged experience of dissociative symptoms even after exposure the traumatic event has ceased. Distinguishing persistent from peritraumatic dissociation is an important factor in the perception of dissociation as helpful or harmful. PTSD and ASD are suggested to be more related to persistent dissociation than peritraumatic dissociation (Briere, Scott, & Weathers, 2005; Harvey & Bryant, 2002). Furthermore, the experience of repeated traumatization, as opposed to a single trauma type, is highly predictive of the dissociative subtype of PTSD (McFarlane, 2007). Service members are often repeatedly exposed to simultaneous traumatic events (e.g., witnessing mutilation, severe human suffering, death of a close friend, combat, explosions, etc.) and are, therefore, more at risk for pathological or persistent dissociation.

Could dissociation be a healthy response to the stress of combat? The perception of dissociation as an indicator of later pathology may not account for the functional utility in emotion modulation for those with occupational exposure to trauma. Dissociative responses during a traumatic event are reportedly common and are not necessarily indicative of later pathology (Cardeña & Spiegel, 1993). A service member's subjective response to trauma may necessitate higher levels of emotional modulation that manifests as dissociation. In such a circumstance, dissociation promotes occupational functioning and is, therefore, adaptive.

References

American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text rev.). Washington, DC: Author.

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Author.

Bremner, J. D., Southwick, S., Brett, E., Fontana, A., Rosenheck, R., & Charney, D. S. (1992). Dissociation and posttraumatic stress disorder in Vietnam combat veterans. American Journal of Psychiatry, 149 , 328–332.

Briere, J., Scott, C., & Weathers, F. (2005). Peritraumatic and persistent dissociation in the presumed etiology of PTSD.  American Journal of Psychiatry, 162, 2295–2301. http://dx.doi.org/10.1176/appi.ajp.162.12.2295

Cardeña, E., & Spiegel, D. (1993). Dissociative reactions to the San Francisco Bay Area earthquake of 1989. American Journal of Psychiatry , 150, 474–478.

Freud, S. (1955). Beyond the pleasure principle, group psychology, and other works. In  J. Strachey (Ed. & Trans.), The standard edition of the complete psychological works of Sigmund Freud (Vol. 18). London, England: Hogarth Press. (Original work published 1920–1922)

Hansen, M., Armour, C., & Elklit, A. (2012). Assessing a dysphoric arousal model of acute stress disorder symptoms in a clinical sample of rape and bank robbery victims.  European Journal of Psychotraumatology, 3, 18201. http://dx.doi.org/10.3402/ejpt.v3i0.18201

Harvey, A. G., & Bryant, R. A. (2002). Acute stress disorder: A synthesis and critique. Psychological Bulletin, 128 , 886–902. http://dx.doi.org/10.1037/0033-2909.128.6.886

Horowitz, M. J. (1986). Stress-response syndromes: A review of posttraumatic and adjustment disorders. Psychiatric Services, 37, 241–249.

Lanius, R. A., Brand, B., Vermetten, E., Frewen, P. A., & Spiegel, D. (2012). The dissociative subtype of posttraumatic stress disorder: Rationale, clinical and neurobiological evidence, and implications. Depression and Anxiety , 29, 701–708. http://dx.doi.org/10.1002/da.21889

Lanius, R. A., Vermetten, E., Loewenstein, R. J., Brand, B., Schmahl, C., Bremner, J. D., & Spiegel, D. (2010). Emotion modulation in PTSD: Clinical and neurobiological evidence for a dissociative subtype. American Journal of Psychiatry,167, 640–647. http://dx.doi.org/10.1176/appi.ajp.2009.09081168

McFarlane, A. C. (2007) Biology not culture explains dissociation in posttraumatic stress disorder. Biological Psychiatry, 73, 296–297. http://dx.doi.org/10.1016/j.biopsych.2012.11.026

Ozer, E. J., Best, S. R., Lipsey, T. L., & Weiss, D. S. (2003). Predictors of posttraumatic stress disorder and symptoms in adults: A meta-analysis. Psychological Bulletin, 129, 52–73. http://dx.doi.org/10.1037/0033-2909.129.1.52