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A network analysis of post-traumatic stress and psychosis symptoms

Published online by Cambridge University Press:  18 May 2020

Amy Hardy*
Department of Psychology, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, SE5 8AF, UK South London & Maudsley NHS Foundation Trust, Bethlem Royal Hospital, Monks Orchard Road, Beckenham, Kent, BR3 3BX, UK
Ciaran O'Driscoll
Research Department of Clinical, Educational and Health Psychology, University College London, Gower Street, London, WC1E 6BT, UK
Craig Steel
The Oxford Institute of Clinical Psychology Training, Oxford, UK
Mark van der Gaag
Department of Clinical Psychology and Amsterdam Public Health Research, VU University, van der Boehorsttraat 7, 1081 BTAmsterdam, The Netherlands Parnassia Psychiatric Institute, Zoutkeetsingel 40, 2512 HNDen Haag, Netherlands
David van den Berg
Department of Clinical Psychology and Amsterdam Public Health Research, VU University, van der Boehorsttraat 7, 1081 BTAmsterdam, The Netherlands Parnassia Psychiatric Institute, Zoutkeetsingel 40, 2512 HNDen Haag, Netherlands
Author for correspondence: Amy Hardy, E-mail:



Understanding the interplay between trauma-related psychological mechanisms and psychotic symptoms may improve the effectiveness of interventions for post-traumatic stress reactions in psychosis. Network theory assumes that mental health problems persist not because of a common latent variable, but from dynamic feedback loops between symptoms, thereby addressing the heterogeneous and overlapping nature of traumagenic and psychotic diagnoses. This is a proof-of-concept study examining interactions between post-traumatic stress symptoms, which were hypothesized to reflect trauma-related psychological mechanisms, and auditory hallucinations and delusions.


Baseline data from two randomised controlled trials (N = 216) of trauma-focused therapy in people with post-traumatic stress symptoms (87.5% met diagnostic criteria for PTSD) and psychotic disorder were analysed. Reexperiencing, hyperarousal, avoidance, trauma-related beliefs, auditory hallucinations and delusional beliefs were used to estimate a Gaussian graphical model along with expected node influence and predictability (proportion of explained variance).


Trauma-related beliefs had the largest direct influence on the network and, together with hypervigilance, were implicated in the shortest paths from flashbacks to delusions and auditory hallucinations.


These findings are in contrast to previous research suggesting a central role for re-experiencing, emotional numbing and interpersonal avoidance in psychosis. Trauma-related beliefs were the psychological mechanism most associated with psychotic symptoms, although not all relevant mechanisms were measured. This work demonstrates that investigating multiple putative mediators may clarify which processes are most relevant to trauma-related psychosis. Further research should use network modelling to investigate how the spectrum of traumatic stress reactions play a role in psychotic symptoms.

Original Article
Copyright © The Author(s), 2020. Published by Cambridge University Press

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