Dissociation can be viewed as the severance of the connections between ideas and emotions. It involves feelings of unreality, estrangement, depersonalisation, and sometimes a loss or shift of identity. A defining characteristic of dissociative disorders is sudden, temporary alterations of consciousness that blot out painful experiences.

The various forms of dissociation include Dissociative Amnesia, characterised by extensive but selective memory loss with no known organic cause. A part of this is dissociative fugue, where a person unexpectedly travels away from home, assumes a new identity, and cannot recall their previous identity. The fugue ends when the person suddenly 'wakes up' with no memory of the events, often associated with overwhelming stress.

Another form is Dissociative Identity Disorder, often referred to as multiple personality, which is the most dramatic of the dissociative disorders. It is associated with traumatic childhood experiences, where the person assumes alternate personalities that may or may not be aware of each other.

The third form is Depersonalisation/Derealisation Disorder, involving a dreamlike state where the person feels separated from both self and reality. In depersonalisation, there is a change of self-perception, and the person’s sense of reality is temporarily lost or changed.