DEFINITION:
The phrase “dissociative identity disorder (DID)” refers toa putative mental illness in which the identity of a patient splits or fragments into two or more distinct and enduring personality states.
Such states, which in general are wholly separate and inaccessible to one another, are manifested alternately.
However, some researchers dispute the existence of DID as a valid diagnostic category.
ETYMOLOGY:
The term DID was officially introduced into the psychological literature in 1994 in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). It was intended to replace the earlier phrase “multiple personality disorder” as a diagnostic category.
The English adjective “dissociative” is allied to the noun “dissociation.” The latter term, in its psychological sense, was introduced into the medical literature by the French psychologist Pierre Janet (1859–1947) in his 1924 book, La médecine psychologique [Psychological Medicine], which was translated into English that same year as Principles of Psychotherapy. The English term “dissociation” is identical in form to the French term.
The English noun “dissociation,” in its general (non-psychological) sense, is attested from the early seventeenth century. It is allied to the verb “dissociate,” which derives from the Latin present participle dissociatus of the verb dissocio, dissociare, meaning “to separate” or “to divide.” These terms, in turn, are compounded from the following two Latin elements:
(1) The inseparable prefix dis-, meaning “separately,” “apart,” or “in different directions”; and
(2) The verb socio, sociare, meaning “to unite,” “to combine,” or “to unite.” Socio, in turn, derives from the adjective socius, which means “sharing” or “accompanying.” The allied substantive form, socius, socii, means “partner,” “companion,” “comrade,” or “associate.”
The English word “identity” is attested from the late sixteenth century. It ultimately derives, via the Middle French noun identité and the Late Latin noun identitas, identitatis, from the Classical Latin pronoun idem, meaning “the same.”
For the etymology of the term “disorder,” see the Glossary entry, borderline personality disorder.
DISCUSSION:
Many investigators believe there is a well-defined and empirically well-confirmed illness that answers to the description of DID. Other scientists demur, insisting that the evidentiary basis for the existence of the disorder is extremely weak.
Those who support the category of DID characterize the illness in several ways above and beyond the basic definition of the alternate manifestation of distinct personality states. For example, DID is thought to include various other pathological states, including amnesia and the deterioration of self-awareness.
Furthermore, on this view, the clinical presentation of symptoms may change over time, with the level of the patient’s impairment varying from minimal to severe.
It is thought that the onset of DID may occur at any age, though symptoms usually first appear between the ages of five and ten. Etiology is often attributed to childhood trauma, especially, sexual abuse.
For the first several decades after its initial identifications, the incidence of what was then known as “multiple personality disorder” was extremely rare. Though the condition began to be described in medical textbooks, few if any practitioners reported having had personal experience with such patients.
Following a spate of popular Hollywood films on the subject, beginning in the 1950s, the incidence of diagnoses of “multiple personality disorder” began to rise.
Then, in the 1990s, during the hysteria surrounding the so-called “repressed memories” of widespread sexual abuse in children, DID (as it had been rechristened) began to be diagnosed far more frequently.
Then, following the debunking of the repressed-memory hysteria, severing the link to childhood sexual abuse in the public mind, the incidence of DID diagnoses declined precipitously.
In short, the history of DID as a diagnostic category has all the hallmarks of a fad.
Nevertheless, as of this writing (2024), DID continues to be listed in the most-recent edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published in 2013.