It is generally agreed that the treatment of multiple personality disorder (MPD) can be a demanding and arduous experience for patient and psychiatrist alike. Difficulties and crisis are intrinsic to the condition, and occur despite therapists' experience and skill. Seasoned clinicians may react with greater composure, and exploit the therapeutic potential of these events more effectively, but are unable to prevent them (C. Wilbur, personal communication, August 1983). In order to appreciate why these patients often prove so difficult, it is helpful to explore certain aspects of the condition's etiology and the patients' was of functioning.

Etiology

The etiology of MPD is unknown, but a wealth of case reports, shared experience, and data from large series^1-3 suggests that MPD is a dissociative response to the traumatic overwhelming of a child's non-dissociative defenses.⁴ The stressor cited most commonly is child abuse. The Four Factor Theory, derived from the retrospective review of 73 cases, and confirmed prospectively in over 100 cases, indicates that MPD develops in an individual who has the capacity to dissociate (Factor 1).⁴ This appears to tap the biological substrate of hypnotizability, without implying its compliance dimensions. Such a person's adaptive capacities are overwhelmed by some traumatic events or circumstances (Factor 2), leading to the enlistment of Factor 1 into the mechanisms of defense. Personality formation develops from natural psychological substrates which are available as building blocks (Factor 3). Some of these are imaginary companionships, ego-states,⁵ hidden observer structures, ⁶ state-dependent phenomena, the vicissitudes of libidinal phases, difficulties in the intrapsychic management of introjection/identification/internalization processes, miscarried of introjection/identification/internalization processes, miscarried mechanisms of defense, aspects of the separation-individuation continuum (especially rapprochement issues), and problems in the achievement of cohesive self and object representation. What leads to the fixation of dividedness is (Factor 4) a failure on the part of significant others to protect the child against further overwhelming, and/or to provide positive and nurturing interactions to allow traumata to be "metabolized" and early or incipient dividedness to be abandoned.

The implications for treatment can only receive brief comment. The clinician is facing a dissociative or hynotic⁷ pathology, and may encounter amnesia, distortions of perception and memory, positive and negative hallucinations, regressions, and revivifications. His patient has been traumatized, and needs to work through extremely painful events. Treatment is exquisitely uncomfortable: it is, in itself, a trauma. Hence resistance is high, the evocation of dissociative defenses within sessions is common, and recovery of memories may be heralded by actions which recapitulate often are dominated by the images of those who have been abusive.

Because of the diversity of Factor 3 substrates, no two MPD patients are structurally the same. MPD is the final common pathway of many different combinations of components and dynamics. Generalizations from accurate observations of some cases may prove inapplicable to others. It is difficult to feel "conceptually comfortable" with these patients. Also, since these patients have not been adequately protected or soothed (Factor 4), their treatment requires a consistent availability, a willingness to hear out all personalities with respect and without taking sides, and a high degree of tolerance so that the patient can be treated without being excessively retraumatized, despite the considerable (and sometimes inordinate and exasperating) demands their treatment makes on the therapist, who will be tested incessantly.

Switching and battles for dominance can create an apparently unending series of crises.

The Instability Of The MPD Patient

An individual suffering MPD has certain inherent vulnerabilities. The very presence of alters precludes the possibility of an ongoing unified and available observing ego and disrupts autonomous ego activities such as memory and skills. Therapeutic activity with one personality may not impact on others. The patient may be unable to address pressing concerns when some personalities maintain they are not involved, others have knowledge which would be helpful but are inaccessible, and still others regard the misfortunes of the other alters to be to their advantage.