Dissociation and Psychosis in Dissociative Identity Disorder and Schizophrenia

Abstract

Dissociative symptoms, first-rank symptoms of schizophrenia, and delusions were assessed in 40 schizophrenia patients and 40 dissociative identity disorder (DID) patients with the Multidimensional Inventory of Dissociation (MID). Schizophrenia patients were diagnosed with the Structured Clinical Interview for the DSM-IV Axis I Disorders; DID patients were diagnosed with the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised. DID patients obtained significantly (a) higher dissociation scores; (b) higher passive-influence scores (first-rank symptoms); and (c) higher scores on scales that measure child voices, angry voices, persecutory voices, voices arguing, and voices commenting. Schizophrenia patients obtained significantly higher delusion scores than did DID patients. What is odd is that the dissociation scores of schizophrenia patients were unrelated to their reports of childhood maltreatment. Multiple regression analyses indicated that 81% of the variance in DID patients' dissociation scores was predicted by the MID's Ego-Alien Experiences Scale, whereas 92% of the variance in schizophrenia patients' dissociation scores was predicted by the MID's Voices Scale. We propose that schizophrenia patients' responses to the MID do not index the same pathology as do the responses of DID patients. We argue that neither phenomenological definitions of dissociation nor the current generation of dissociation instruments (which are uniformly phenomenological in nature) can distinguish between the dissociative phenomena of DID and what we suspect are just the dissociation-like phenomena of schizophrenia.

The relationship between dissociation and voices: A systematic literature review and meta-analysis

“…Within logistic regression analysis Dorahy et al (2009) found that five voice-related dependent variables (hearing two or more voices, being told what to do by voices, feeling controlled by voices, voice content relating to someone influential in your life and voices replaying past memories) were significantly predicted by the DES-T in voice-hearers with either a schizophrenia or DID diagnoses. In contrast to the significant differences found between schizophrenia and DID groups by Dorahy et al (2009) and Laddis and Dell (2012), Honig et al (1998) found no significant differences between schizophrenia and DID groups regarding voice characteristics. A potential explanation for the differing results found between studies may be that small sample sizes were used, consequently limiting the statistical power in order to detect differences between variables.…”

“…Similarly, Laddis and Dell (2012) found no significant correlation between trauma exposure (TEQ score) and dissociation (MID score)…”

“…Three studies compared participants with a DID diagnosis to other groups of participants, including those with a diagnosis of schizophrenia (Dorahy et al, 2009;Honig et al, 1998;Laddis & Dell, 2012). Although these studies often did not test for associations between measures of voices and dissociation directly, it can be argued that tentative evidence may be inferred from their reported analyses of voice characteristics reported by DID patients (a clinical group characterised by pervasive dissociative experiences) when compared to other diagnostic groups.…”

“…Although these studies often did not test for associations between measures of voices and dissociation directly, it can be argued that tentative evidence may be inferred from their reported analyses of voice characteristics reported by DID patients (a clinical group characterised by pervasive dissociative experiences) when compared to other diagnostic groups. Two of the identified studies found that, in comparison to participants with a diagnosis of schizophrenia, participants with a diagnosis of DID reported earlier onset of voices, hearing two or more voices, hearing children's voices, hearing more angry and persecutory voices as well as greater prevalence of other forms of hallucinations (Dorahy et al, 2009;Laddis & Dell, 2012). Within logistic regression analysis Dorahy et al (2009) found that five voice-related dependent variables (hearing two or more voices, being told what to do by voices, feeling controlled by voices, voice content relating to someone influential in your life and voices replaying past memories) were significantly predicted by the DES-T in voice-hearers with either a schizophrenia or DID diagnoses.…”

Dissociation, shame, complex PTSD, child maltreatment and intimate relationship self-concept in dissociative disorder, chronic PTSD and mixed psychiatric groups

“…It seems the so-called positive symptoms of schizophrenia, borderline symptoms and the pathological manifestations of dissociation may discriminate those with severe dissociative disorders from those with chronic/dissociative PTSD or less severe dissociative disorders. Empirical work has noted the high prevalence of Schneiderian, borderline and pathological dissociative symptoms in severe dissociative disorders (Ellason et al, 1996;Fink and Golinkoff, 1990;Laddis and Dell, 2012;Ross et al, 1990), but few studies have used child abuse-related chronic PTSD comparison groups whose abuse severity overall was similar to those of the DD group. Interestingly, a study of the same data set examining abuse and neglect more closely found that the DD and Chr-PTSD samples were similar on all forms of abuse severity except sexual abuse, where the DD group was higher (Dorahy et al, in preparation).…”