Failure to diagnose dissociative identity disorder is inevitable with the interview taught in American psychiatry residency training programs

Psychiatric diagnosis depends on an interview called the Mental Status Examination (MSE). Psychiatrists are not able to diagnose a disorder if the MSE fails to elicit its symptoms, its Diagnostic Criteria.

The Diagnostic Criteria for dissociative identity disorder (multiple personality disorder), found in DSM-5 (the diagnostic manual), may be abbreviated as follows:

Criterion A: alternate identities

Criterion B: memory gaps

Interviewing the “Host” Identity

Since the psychiatrist will be interviewing the patient’s “regular” or “host” identity—who is unaware of any other identities—neither the psychiatrist nor the patient (the host identity) will suspect dissociative identity disorder.

Alternate Identities Hide and Remain Incognito

Alternate identities will usually hide during psychiatric interviews. But even if an alternate identity does come out during the interview, it will not give its name or identify itself. It will answer to the patient’s regular name in order to fool the psychiatrist.

Why? Because they didn’t make this appointment. They are not the patient. And they see the psychiatrist as being an ally of the host identity in the doctor-patient relationship. Moreover, they fear that if the psychiatrist knew about them, he would try to get rid of them, out of loyalty to the host identity, his patient.

Memory Gaps as Footprints

Therefore, since the psychiatrist will not see—or at least not knowingly see—alternate identities, the key to making this diagnosis is to screen for it by getting a history of memory gaps. The host identity is usually aware of having had memory gaps, and will give that history if asked, but only if asked, because the gaps are nothing new, and the host has always tried to ignore them.

If there is a history of memory gaps—and if they have no medical or neurological cause—then the gaps may be periods of time during which alternate identities have been “out.” So getting a history of memory gaps is like finding the footprints of alters, but not the alters themselves.

The MSE and Memory Gaps

Does the traditional MSE interview ask patients if they have a history of memory gaps? Unfortunately, it does not. It evaluates short-term memory and long-term memory. It does not ask about memory gaps.

If alcoholism is at issue, the traditional MSE may inquire about alcoholic blackouts. But it fails to inquire about nonalcoholic “dry” blackouts.

The Formal Diagnosis 

The diagnosis of dissociative identity disorder is not made unless and until the clinician knowingly meets, and has conversations with, the alternate identities (Criterion A), and then finds that the host identity has amnesia (memory gaps) (Criterion B) for those conversations.

However, as explained above, the diagnostic process usually starts with Criterion B (memory gaps), and eventually leads to Criterion A (alternate identities).

“But I never see that.”

When told that a colleague has made the diagnosis of dissociative identity disorder, most American psychiatrists wonder why, if it’s real, they never see it. The reason is that the traditional MSE fails to ask patients if they have a history of memory gaps.

Except for the rare cases in which alternate identities are overt in the initial interview, it is only after getting a history of memory gaps, and then finding out what caused the memory gaps, that a psychiatrist will make this diagnosis.

Most American psychiatrists think that they never see such cases, because they do not routinely ask their patients if they have a history of memory gaps.

Books That Illustrate the Problem

Note: These books were chosen, because they are excellent in other regards.

1. Mark Zimmerman, M.D. Interview Guide for Evaluating DSM-5 Psychiatric Disorders and the Mental Status Examination. East Greenwich, RI, Psych Products Press, 2013.

Patients are never asked if they have a history of memory gaps, and the book never even mentions dissociative identity disorder.

2. Paula T. Trzepacz, M.D., Robert W. Baker, M.D. The Psychiatric Mental Status Examination. New York, Oxford University Press, 1993.

Patients are never asked if they have a history of memory gaps, and the book never even mentions multiple personality disorder (the name of the disorder at the time this book was published).

3. David J. Robinson, M.D. Brain Calipers 2nd Ed.: Descriptive Psychopathology and the Psychiatric Mental Status Examination. Rapid Psychler Press, 2001.

Patients are never asked if they have a history of memory gaps, and the book never even mentions dissociative identity disorder.

4. Abraham M. Nussbaum, M.D. The Pocket Guide to the DSM-5 Diagnostic Exam. Washington, D.C., American Psychiatric Publishing (A Division of American Psychiatric Association), 2013.

At first, this guide looks enlightened. Its general psychiatric interview includes the following screening question under the heading of Dissociation: “Everyone has trouble remembering things sometimes, but do you ever lose time, forget important details about yourself, or find evidence that you took part in events you cannot recall?” And in its brief chapter on Dissociative Disorders, this guide includes dissociative identity disorder.

However, in contradiction to the above, its outline of the Mental Status Examination includes “recent and remote” memory, but omits memory gaps. And in its chapter, “A Brief Version of DSM-5”—covering, the author implies, the really important disorders—it omits dissociative identity disorder (even though the author, having read DSM-5, should have known that dissociative identity disorder has a greater prevalence than schizophrenia).

Therefore, the mixed-message of this guide is that the conscientious psychiatrist should screen for multiple personality by asking a question about memory gaps, but if the psychiatrist doesn't have time to do everything, and must focus only on what, in the author’s opinion, is really important, then screening for dissociative identity disorder can be omitted.

In short, even when American psychiatrists are taught how to screen for dissociative identity disorder, they are told not to bother.

In conclusion, to make the MSE capable of screening for dissociative identity disorder, its evaluation of memory must include memory gaps. This would require the addition of one word to the outline of the MSE taught to psychiatrists:

Traditional MSE

Memory: short-term, long-term

Revised MSE

Memory: short-term, long-term, gaps