A comparison between auditory hallucinations, interpretation of voices, and formal thought disorder in dissociative identity disorder and schizophrenia spectrum disorders.
Martin J Dorahy, Amy Nesbit, Rachael Palmer, Bailey Wiltshire, Jacinta R Cording, Donncha Hanna, Lenaire Seager, Warwick Middleton
Journal of clinical psychology September 1, 2023 Peer reviewed DOI: 10.1002/jclp.23522 via PubMed
Summary
People with dissociative identity disorder (DID) experience voices as more internal, generated by themselves, louder, and less controllable than do people with schizophrenia-spectrum disorders (SSD). Those with DID also report more thought disorder symptoms. After accounting for sex, depersonalization, and childhood maltreatment, differences in loudness and controllability disappear, but the SSD group shows more distress, metaphysical beliefs about voices, and specific thought disorder symptoms like incoherence and word substitution. These features may indicate more psychotic processes.
Study at a glance
| Design | observational cohort |
|---|---|
| Sample size | 89 |
| Population | adults with dissociative identity disorder (n=44) or schizophrenia-spectrum disorders (n=45) |
| Key finding | DID participants perceived voices as more internal and generated by themselves, while SSD participants reported more distress, metaphysical beliefs, and certain thought disorder symptoms after controlling for covariates. |
Abstract
Dissociative identity disorder (DID) and schizophrenia-spectrum disorders (SSD) share some overlapping phenomenological features making accurate diagnosis more difficult. Childhood abuse and depersonalization have been associated with psychotic symptoms across psychological disorders but their relationship to psychotic phenomenology remains understudied. The present study used quantitative measures to examine (1) similarities and differences in phenomenological voice hearing experiences, interpretations of voices, and thought disorder symptoms in individuals with DID (n = 44) or SSD (n = 45), and (2) whether depersonalization and childhood maltreatment influenced the initial pattern of findings. DID participants perceived their voices as being more internally located and generated, louder, and uncontrollable than SSD participants. Furthermore, the DID participants endorsed a greater frequency of thought disorder symptoms. Adding the covariates (sex, depersonalization, and child maltreatment) did not change the findings associated with location and origin of voices, and derailment, but there were now no differences in loudness or controllability. However, the schizophrenia sample reported more distress and metaphysical beliefs associated with voices, as well as more thought disorder incoherence and word substitution with the covariates controlled. While tentative, metaphysical interpretations of voices, incoherent thoughts and word substitution may reflect more psychotic processes.