The DID patient should be seen as a whole adult person with the identities sharing responsibility for daily life. Despite patients’ subjective experience of separateness, clinicians must keep in mind that the patient is a single person and generally must hold the whole person (i.e., system of alternate identities) responsible for the behavior of any or all of the constituent identities, even in the presence of amnesia or the sense of lack of control or agency over behavior.From p8 International Society for the Study of Trauma and Dissociation. (2011). Guidelines for treating dissociative identity disorder in adults, third revision: Summary version. Journal of Trauma & Dissociation, 12, 188–212.

Patients with complex trauma may at times develop extreme reactions to something the therapist has said or not said, done or not done. It is wise to anticipate this in advance, and perhaps to note this anticipation in initial communications with the patient. For example, one may say something like, "It is likely in our work together, there will be a time or times when you will feel angry with me, disappointed with me, or that I have failed you. We should except this and not be surprised if and when it happens, which it probably will." It is also vital to emphasize to the patient that despite the diagnosis and experience of dividedness, the whole person is responsible and will be held responsible for the acts of any part. p174