Richard Ghia-Wilberforce, 2007. Edited significantly in 2017.

The traditional medical model of multiplicity treats it as a form of dissociation adopted by people who have experienced severe abuse. It conceptualises multiplicity as a delusional defence mechanism in which ‘alters’ split from the ‘host personality’ during severe trauma that occurs in early childhood. This model does not see members of a multiple system as full individuals in their own right; rather, it views them as fragments, ego states or alters to be integrated into a single personality.

This model, or a variation of it, may suit dissociative systems for whom the classical DID model is appropriate. It does not, however, apply in all cases, even if a system has gone through trauma.

Non-dissociative multiple systems should not have their experience described using that model because it presupposes two things that may or may not be true:

  • that multiplicity in and of itself is harmful and must be corrected; and
  • that the formation of system-members must always match the medical model precisely.

The dissociation model and most of its resultant therapeutic methods suggest that it is malign and unnatural for more than one mind to inhabit a single body. Some systems, whether trauma-based or not, find that being multiple has allowed them to live healthier lives than they would have done otherwise. Some systems do struggle with co-operation, sharing time and things like self-harm, but those difficulties are not intrinsic to multiplicity itself. Disordered systems are a subtype, not the totality.

The idea, moreover, of valuing a cohesive, singular self-concept over other conceptualisations of selfhood is more of a Western cultural construct rather than a scientific reality. If we define personhood by considering personal agency and independent thought, members of plural systems would certainly qualify. If, however, we base it solely on the body being inhabited, they would not. I believe personal agency and independent thought should be given more weight in determining personhood.

Multiplicity is simply the presence of more than one conscious agent within a body, and this definition does not require that systems should adhere entirely to the medical model. There are certainly those who do, but that is not a universal experience. Some systems consider themselves to have been born multiple. An early example of this is Mary Reynolds’ case, in which a woman had a multiple system without any influence from doctors or known abuse history.

Strict interpretations of the medical model define personhood clearly, with no regard for individuals’ identities. The medical model postulates that the only ‘real’ person within a group is the gestalt that is associated with the system’s legal identity and collective background. The ‘birth person’ may or may not be an actual person at all, but that has no bearing on it. Although such details are important when dealing with society at large, they can be different to a individual system-member’s self-perception. It is possible to value individual identities whilst recognising the role that collective experiences play.

Plurality comprises multifarious experiences, and the idea that all plurality is a manifestation of harmful dissociative coping mechanisms is an oversimplification based on Western cultural tropes and misconceptions about the meaning of mental health for a given person or system. We would do well to recognise that this experience is complex and to avoid presenting any interpretation as the single true answer.

Addendum (28 July 2009) Therapists subscribing to the medical model have modified their stance over the past few years, and they are beginning to understand that plural collectives can indeed be treated as separate individuals, rather than ‘alters’ or ‘parts’. –M.D.

(edit by RGW, 31 Mar 2012, for pronoun use)
(edit by RGW, 21 Jan 2013, for wording)