Dissociation Following Traumatic Stress: Etiology and Treatment

The cost of this subjective detachment appears to be a disruption of mental functions that are crucial to the development of identity, self-control, and emotion regulation.

“The cost of this subjective detachment appears to be a disruption of mental functions that are crucial to the development of identity, self-control, and emotion regulation [1, 16, 36, 37, 116].”

Functional sensory deafferentation provides a means of modulating or shutting down overwhelming sensory information, and mimicking death or 'death-feigning' ensues.

“Withdrawal of sympathetic activity and activation of parasympathetic activity occur as the organism becomes increasingly unresponsive to sensory stimulation, including pain, representing the beginning of functional sensory deafferentation at the level of the cortico-sensory pathways (e.g., reduced integration of auditory, visual, proprioceptive, and somatosensory information from the thalamus to”

Withdrawal of sympathetic activity and activation of parasympathetic activity occur as the organism becomes increasingly unresponsive to sensory stimulation, including pain, representing the beginning of functional sensory deafferentation at the level of the cortico-sensory pathways.

“Withdrawal of sympathetic activity and activation of parasympathetic activity occur as the organism becomes increasingly unresponsive to sensory stimulation, including pain, representing the beginning of functional sensory deafferentation at the level of the cortico-sensory pathways (e.g., reduced integration of auditory, visual, proprioceptive, and somatosensory information from the thalamus to”

In cases where the organism determines it has little to no chance of survival, unresponsive immobility or death feigning may occur in an attempt to decrease predator interest, which may lead to tonic or collapsed immobility.

“Critically, in cases where the organism determines it has little to no chance of survival, unresponsive immobility or death feigning may occur in an attempt to decrease predator interest, which may lead to tonic or collapsed immobility (Kozlowska et al., 2015;Schauer and Elbert, 2010).”

Initial responses to confrontation with threat are accompanied by an orienting response characterized by bradycardia and inhibition of the startle response.

“In this model, initial responses to confrontation with threat are thought to be accompanied by an orienting response characterized by bradycardia and inhibition of the startle response (Schauer and Elbert, 2010).”

Regulation of thalamic activity may allow an organism to shut down peripheral sensory mechanisms in order to enter a state of collapsed immobility.

“Accordingly, Schauer and Elbert (2010) suggest that regulation of thalamic activity may allow an organism to shut down peripheral sensory mechanisms in order to enter a state of collapsed immobility.”

In extreme situations, a final stage of response may be mediated by a shut-down of peripheral vagal activity and a vasovagal response leading to fainting or flaccid immobility.

“Finally, in extreme situations, a final stage of response may be mediated by a shut-down of peripheral vagal activity and a vasovagal response leading to fainting or flaccid immobility (Schauer and Elbert, 2010) (see Figs. 1 and 2).”

Re-enactment of defence stages, including tonic and collapsed immobility, occurs in response to internal (e.g., intrusion symptoms) or external environmental trauma cues.

“Specifically, Schauer and Elbert (2010) describe re-enactment of defence stages, including tonic and collapsed immobility, in response to internal (e.g., intrusion symptoms) or external environmental trauma cues.”

Altered states of arousal, as in the defence cascade model of dissociation, are linked to reduced cognitive functioning among highly dissociative individuals.

“Here, we propose further a neurobiological model linking altered states of arousal, as in the defence cascade model of dissociation (Schauer and Elbert, 2010;Kozlowska et al., 2015), to reduced cognitive functioning among highly dissociative individuals (see Fig. 3).”

The shutdown model describes two distinct response profiles: Type 1 'uproar-PTSD', characterized by dominant sympathetic activation, and Type 2 'shutdown-PTSD', characterized by dominant parasympathetic activation.

“the shutdown model describes two distinct response profiles: the Type 1 ‘uproar-PTSD’, characterized by dominant sympathetic activation, and Type 2 ‘shutdown-PTSD’, characterized by dominant parasympathetic activation”

An individual who exhibits a parasympathetic-dominant reaction (e.g. flag or faint) to the trauma is more likely to experience an acute post-traumatic dissociative response, accompanied by inhibition of the SNS, activation of the PNS, and reduction in heart rate and blood pressure.

“Thus, an individual who exhibits a parasympathetic-dominant reaction (e.g. flag or faint) to the trauma is more likely to experience an acute post-traumatic dissociative response, accompanied by inhibition of the SNS, activation of the PNS, and reduction in heart rate and blood pressure.”

The shutdown model classifies six distinct stages of threat response.

“The shutdown model by Schauer and Elbert (2010) closely resembles the defense cascade model, but classifies six distinct stages of threat response.”

The stable dissociative response pattern may be a conditioned automatic response to stressors and perceived threat.

“the characterization of the shutdown model of PTSD suggests that the stable dissociative response pattern may be a conditioned automatic response to stressors and perceived threat (Schauer & Elbert, 2010).”

According to the defense cascade and shutdown models, individuals who experience dissociation during the initial traumatic event should bypass the tonic immobility state and enter a hypoaroused state.

“According to the defense cascade (Lanius et al., 2018) and shutdown models (Schauer & Elbert, 2010), individuals who experience dissociation during the initial traumatic event should bypass the tonic immobility state and enter a hypoaroused state.”