a1 School of Psychology, Bangor University, Bangor, Gwynedd, UK
a2 Institute of Psychology, Health and Society, University of Liverpool, UK
a3 Department of Psychology, University of Wollongong, Australia
Background It has been proposed that the relationship between childhood trauma and hallucinations can be explained by dissociative processes. The present study examined whether the effect of childhood trauma on hallucination-proneness is mediated by dissociative tendencies. In addition, the influence of dissociative symptoms on a cognitive process believed to underlie hallucinatory experiences (i.e. reality discrimination; the capacity to discriminate between internal and external cognitive events) was also investigated.
Method Patients with schizophrenia spectrum disorders (n=45) and healthy controls (with no history of hallucinations; n=20) completed questionnaire measures of hallucination-proneness, dissociative tendencies and childhood trauma, as well as performing an auditory signal detection task.
Results Compared to both healthy and non-hallucinating clinical controls, hallucinating patients reported both significantly higher dissociative tendencies and childhood sexual abuse. Dissociation positively mediated the effect of childhood trauma on hallucination-proneness. This mediational role was particularly robust for sexual abuse over other types of trauma. Signal detection abnormalities were evident in hallucinating patients and patients with a history of hallucinations, but were not associated with pathological dissociative symptoms.
Conclusions These results are consistent with dissociative accounts of the trauma-hallucinations link. Dissociation, however, does not affect reality discrimination. Future research should examine whether other cognitive processes associated with both dissociative states and hallucinations (e.g. deficits in cognitive inhibition) may explain the relationship between dissociation and hallucinatory experiences.
(Received February 16 2011)
(Revised July 01 2011)
(Accepted August 13 2011)
(Online publication September 06 2011)
c1 Address for correspondence: Dr F. Varese, Institute of Psychology, Health and Society – Division of Mental Health and Behavioural Sciences, Waterhouse buildings, Block B (2nd floor), University of Liverpool, Liverpool, L69 3GB, UK. (Email: Filippo.Varese@liverpool.ac.uk)