The Sense of Self Over Time: Assessing Diachronicity in Dissociative Identity Disorder, Psychosis and Healthy Comparison Groups.

Dissociative experiences have been associated with diachronic disunity. Yet, this work is in its infancy. Dissociative identity disorder (DID) is characterized by different identity states reporting their own relatively continuous sense of self. The degree to which patients in dissociative identity states experience diachronic unity (i.e., sense of self over time) has not been empirically explored. This study examined the degree to which patients in dissociative identity states experienced diachronic unity. Participants were DID adults (n=14) assessed in adult and child identity states, adults with a psychotic illness (n=19), adults from the general population (n=55), children from the general population (n=26) and adults imagining themselves as children (n=23). They completed the Diachronic Disunity Scale (DDS), the Dissociative Experiences Scale (DES), and the Self-Concept Clarity Scale (SCCS). Diachronic disunity was not limited to psychiatric groups, but evident to some degree in all adult and child samples. The DID adult sample experienced more dissociation and self-confusion than the psychosis and adult comparison groups, but did not differ on the diachronic measure. DID patients in their child identity states and child comparisons showed disunity and were significantly different from child simulators, who showed relatively more unity. Results suggest that DID patients in either adult or child dissociative identity states, like those in other samples, do not universally experience themselves as having a consistent sense of self over time.

Inter-identity amnesia for neutral episodic self-referential and autobiographical memory in Dissociative Identity Disorder: An assessment of recall and recognition.

Amnesia is a core diagnostic criterion for Dissociative Identity Disorder (DID), however previous research has indicated memory transfer. As DID has been conceptualised as being a disorder of distinct identities, in this experiment, behavioral tasks were used to assess the nature of amnesia for episodic 1) self-referential and 2) autobiographical memories across identities. Nineteen DID participants, 16 DID simulators, 21 partial information, and 20 full information comparison participants from the general population were recruited. In the first study, participants were presented with two vignettes (DID and simulator participants received one in each of two identities) and asked to imagine themselves in the situations outlined. The second study used a similar methodology but with tasks assessing autobiographical experience. Subjectively, all DID participants reported amnesia for events that occurred in the other identity. On free recall and recognition tasks they presented a memory profile of amnesia similar to simulators instructed to feign amnesia and partial information comparisons. Yet, on tests of recognition, DID participants recognized significantly more of the event that occurred in another identity than simulator and partial information comparisons. As such, results indicate that the DID performance profile was not accounted for by true or feigned amnesia, lending support to the idea that reported amnesia may be more of a perceived than actual memory impairment.

Transfer of episodic self-referential memory across amnesic identities in dissociative identity disorder using the Autobiographical Implicit Association Test.

Individuals with dissociative identity disorder (DID) often report having no access to autobiographical experiences encoded by other identities. This research used the autobiographical Implicit Association Test (aIAT) to determine whether there was transfer of episodic self-referential memory events across amnesic identities. Nineteen DID individuals, 16 DID simulators, and 41 comparison participants (divided into amnesic and nonamnesic groups) engaged with an audio vignette of embarrassing scenarios to produce the experience of episodic self-referential events. Results showed transfer of episodic self-referential memory using the aIAT across identities that reported no conscious awareness of encoded content in DID. These aIAT results in DID patients were similar to the nonamnesic comparison group and the simulator group, and differed from the amnestic comparison group. These results are in line with previous literature showing transfer of memories, but extends this work to episodic self-referential memory. (PsycINFO Database Record (c) 2018 APA, all rights reserved).