If you’ve ever driven to a familiar place and arrived not remembering how you got there, you could be said to ‘dissociate’ from time to time – that is, to disconnect your conscious mind from your bodily experience.

Dissociation is an adaptive, automatic and universal mechanism of the mind that shapes our conscious sense of self. Contemporary thinkers see each of us as a collection of ‘self-states’ – aspects of self, each with its own set of feelings, memories, values, and thinking capacity. At a level of healthy functioning, we move fluidly between self-states to adapt to our environment. However in some circumstances, dissociation will lock out particular self-states or prevent them from developing.

Dissociation and trauma

Imagine a situation in which your survival is at stake, for example a car crash or violent assault. In the face of a potentially annihilating event like these, we may be terrified yet powerless. This is trauma (even if the anticipated event does not ultimately happen). Unable to fight or to flee, our only remaining possible response is to freeze, effectively to dissociate. We see this in animals, when they ‘play dead’ in the face of predator threat. Bodily systems drastically slow down, and the overwhelmed conscious mind (or left brain) goes offline.

Survival through dissociation comes at a price. As the conscious mind is not there to process emotion, record, remember or make sense of what is happening, the traumatic experience is registered only somatically. If we later see, hear or smell something reminiscent of the trauma, the somatic memory may be triggered. Still disconnected from the part of the brain that remembers the event as a narrative within a time and place, the trauma will feel as if it’s happening again now. This is PTSD. To protect us from the intolerable experience of being re-traumatised, dissociation may kick in whenever the body (linked to the right brain) senses potential triggers, creating huge disruption to living our lives.