Dissociation is simply a “disruption of the normal integration of experience” (Chu 1998). It is something that everyone experiences as we organise and compartmentalise our experiences and memories.
This can be a normal, healthy and useful process. As therapists, we use a form of dissociation to keep ourselves apart from the effects of other people’s experiences.
For trauma victims, dissociation can be used to compartmentalise conflicting experiences. e.g. the love of a parent and the abuse of the same parent.
This excellent paper from recognised trauma therapist, Janina Fisher, explains how we can better understand dissociation in out clients: what to look for, what to ask and how to move forward with treatment.
I highly recommend that you read her views.