Hallucinations, delusions, and formal thought disorder in dissociative identity disorder and schizophrenia.
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
Psychotic symptoms that are usually associated with schizophrenia but also experienced in dissociative identity disorder (DID) can bring about diagnostic difficulties. Furthermore, some psychotic symptoms have been associated with childhood abuse, but the combination of childhood and adulthood abuse, and their relationship with psychotic symptoms is relatively unexplored. The present study used a battery of quantitative measures for two investigations. Firstly, phenomenological similarities and differences in hallucinations, delusions, and formal thought disorder were compared in three groups of patients: 1) DID with childhood abuse (n = 29), 2) DID with childhood and adulthood abuse (n = 21), and 3) schizophrenia (n = 17). No psychotic symptom differences were found between the two DID groups, however a number of differences between one or both of the DID groups and the schizophrenia group were found. DID participants reported higher auditory hallucination distress, higher interpretations of loss of control related to auditory hallucinations, louder auditory hallucinations, and higher frequencies of other modalities of hallucinations compared to the schizophrenia group. Secondly, relationships between childhood and adulthood abuse and psychotic symptoms were examined. Childhood and adulthood abuse accounted for significant variance in other modalities of hallucinations (visual, tactile, olfactory, and gustatory). Childhood abuse accounted for significant variance in auditory hallucination attributions, delusion distress and conviction, and formal thought disorder. The results of this study may aid in diagnostic accuracy and access to appropriate treatments for people with both disorders, and may help screening for psychotic symptoms in people who have been abused in childhood.