Interidentity memory transfer in dissociative identity disorder.

Abstract

Controversy surrounding dissociative identity disorder (DID) has focused on conflicting findings regarding the validity and nature of interidentity amnesia, illustrating the need for objective methods of examining amnesia that can discriminate between explicit and implicit memory transfer. In the present study, the authors used a cross-modal manipulation designed to mitigate implicit memory effects. Explicit memory transfer between identities was examined in 7 DID participants and 34 matched control participants. After words were presented to one identity auditorily, the authors tested another identity for memory of those words in the visual modality using an exclusion paradigm. Despite self-reported interidentity amnesia, memory for experimental stimuli transferred between identities. DID patients showed no superior ability to compartmentalize information, as would be expected with interidentity amnesia. The cross-modal nature of the test makes it unlikely that memory transfer was implicit. These findings demonstrate that subjective reports of interidentity amnesia are not necessarily corroborated by objective tests of explicit memory transfer.

Inter-Identity Autobiographical Amnesia in Patients with Dissociative Identity Disorder

“…Again, inconsistent with the hypothesis of interidentity amnesia, participants recognized List A words in their amnesic dissociative identity. These results were replicated and extended in a different patient group by Kong et al [14] who included a cross-modal manipulation designed to mitigate implicit memory effects. Furthermore, Huntjens et al [17] used negatively and positively valenced words to test whether the presumptive amnesic barrier is especially impermeable to negative material, as implied by the belief that amnesia in DID functions to block painful memories.…”

“…In experimental research, compartmentalization is assessed by one identity learning new information and another identity, reporting amnesia for the learning trial, being tested on retrieval of this information. The majority of compartmentalization studies in DID included neutral stimulus material, usually unrelated words or drawings of common objects [4]–[14], whereas only a few studies have also included emotionally valenced stimulus material [15]–[17]. One example of a controlled study concerning neutral stimulus material is an interference paradigm [11], [14].…”

“…The majority of compartmentalization studies in DID included neutral stimulus material, usually unrelated words or drawings of common objects [4]–[14], whereas only a few studies have also included emotionally valenced stimulus material [15]–[17]. One example of a controlled study concerning neutral stimulus material is an interference paradigm [11], [14]. First, we asked participants to learn a list of words containing trauma-related, positive, and neutral words (list A).…”

A Review of Published Research on Adult Dissociative Identity Disorder

“…Thirteen studies emerged in the review that contained a comparison group of people without DID who were simulating DID in some way. Nine studies found no difference between people with DID and DID simulators in terms of the main dependent variables; the measures in these studies included implicit memory (Allen and Movius, 2000;Huntjens et al, 2002Huntjens et al, , 2003Huntjens et al, , 2005aHuntjens et al, , 2005bHuntjens et al, , 2006Huntjens et al, , 2007Kong et al, 2008), event-related potential (Allen and Movius, 2000), and the Dissociative Experiences Scale (Thomas, 2001). Differences that emerged in the other studies included subscale scores on a measure of faking mental illness , SCID-D scores, eye-roll sign for hypnotic potential , reaction times to angry faces , and electroencephalogram coherence .…”

Measuring fragmentation in dissociative identity disorder: the integration measure and relationship to switching and time in therapy

“…Much of the previous research on DID has used samples of one to seven participants (e.g., Kong, Allen, & Glisky, 2008; Loewenstein, Hamilton, Alagna, Reid, & deVries, 1987; Nissen, Ross, Willingham, MacKenzie, & Schacter, 1988; Peters, et al, 1998; Schacter, Kihlstrom, Kihlstrom, & Berren, 1989; Tsai, et al, 1999), so having a sample this size is not unusual in research in this field. Reinders and colleagues (2006) also had 11 participants.…”