ミラーニューロンと解離 15

The essence of this definition of DID involves “marked discontinuities in the sense of self and agency.” However, this statement in ICD-11(draft) does not state clearly how the sense of self is disrupted. DSM-5’s similar definition of DID states more clearly the way this disruption is experienced subjectively by the individual with DID.

Individuals with dissociative identity disorder may report the feeling that they have suddenly become depersonalized observers of their own speech and actions, which they may feel powerless to stop (sense of self). Such individuals may also report perceptions of voices (e.g., a child's voice; crying; the voice of a spiritual being). In some cases, voices are experienced as multiple, perplexing, independent thought streams over which the individual experiences no control. Strong emotions, impulses, and even speech or other actions may suddenly emerge, without a sense of personal ownership or control (sense of agency)(American Psychiatric Association, 2013).

　What this statement in DSM-5 is understood as hallucinatory perceptions and “made” experiences. These are experiences where the personality A is intruded upon by the voices and behaviors of personality B, or vice versa, and thus A or B’s sense of agency is seriously impaired. However, many individuals with DID do not have these experiences in majority of times. Quite often, when A is active, B might be mostly absent (probably in a form of being “asleep” etc.) whereas when B is active, he feels independent and undisturbed by anybody either. In fact, the so-called host personality could be oblivious to the existence of any other personalities for a long time until some circumstantial evidences crop up indicating otherwise. If it is so, the patient with DID might not have these essential experiences of the disruption of the sense of self very often.  The question is whether it is rational to consider these “made” experiences as DID’s essential problem of the disturbance of the sense of self while they are not necessarily present in their experiences.

   One possible speculation is that in the individual with DID, a previously integrated personality ( the one which might have been existed before their identities are split and dissociated) is hypothesized in clinicians’ mind and that virtually integrated self suffers its own integrity by having multiple and interchanging identities. Another possibility is to consider that these identities are only partial and incomplete one and the self disturbance is found in its existence. One of the experts on the theory of Dissociation wrote as follows:

We describe the division of personality in terms of dissociative parts of the personality. This choice of term emphasizes the fact that dissociative parts of the personality together constitute one whole, yet are self-conscious, have at least a rudimentary sense of self …　and are generally more complex than a single psycho-biological state. These dissociative parts are mediated by action systems.

However, a question rises, which is whether we can really speculate a "partial" sense of self either theoretically, experiencially or clinically. Can our sense of self be experienced partially?