Psychological Medicine

  • Psychological Medicine / Volume 43 / Issue 12 / December 2013, pp 2673-2684
  • Copyright © Cambridge University Press 2013 The online version of this article is published within an Open Access environment subject to the conditions of the Creative Commons Attribution-NonCommercial-ShareAlike licence <>. The written permission of Cambridge University Press must be obtained for commercial re-use.
  • DOI: (About DOI), Published online: 27 March 2013

Original Articles

Paranoia and post-traumatic stress disorder in the months after a physical assault: a longitudinal study examining shared and differential predictors

D. Freemana1 c1, C. Thompsona2, N. Vorontsovaa2, G. Dunna3, L.-A. Cartera3, P. Garetya2, E. Kuipersa2, M. Slatera4a5, A. Antleya1a4, E. Glucksmana6 and A. Ehlersa7

a1 Department of Psychiatry, University of Oxford, UK

a2 Department of Psychology, King's College London, Institute of Psychiatry, UK

a3 Centre for Biostatistics, Institute of Population Health, University of Manchester, UK

a4 Department of Computer Science, University College London, UK

a5 Institució Catalana de Recerca i Estudis Avançats (ICREA), University of Barcelona, Spain

a6 Emergency Department, King's College Hospital, London, UK

a7 Department of Experimental Psychology, University of Oxford, UK


Background Being physically assaulted is known to increase the risk of the occurrence of post-traumatic stress disorder (PTSD) symptoms but it may also skew judgements about the intentions of other people. The objectives of the study were to assess paranoia and PTSD after an assault and to test whether theory-derived cognitive factors predicted the persistence of these problems.

Method At 4 weeks after hospital attendance due to an assault, 106 people were assessed on multiple symptom measures (including virtual reality) and cognitive factors from models of paranoia and PTSD. The symptom measures were repeated 3 and 6 months later.

Results Factor analysis indicated that paranoia and PTSD were distinct experiences, though positively correlated. At 4 weeks, 33% of participants met diagnostic criteria for PTSD, falling to 16% at follow-up. Of the group at the first assessment, 80% reported that since the assault they were excessively fearful of other people, which over time fell to 66%. Almost all the cognitive factors (including information-processing style during the trauma, mental defeat, qualities of unwanted memories, self-blame, negative thoughts about self, worry, safety behaviours, anomalous internal experiences and cognitive inflexibility) predicted later paranoia and PTSD, but there was little evidence of differential prediction.

Conclusions Paranoia after an assault may be common and distinguishable from PTSD but predicted by a strikingly similar range of factors.

(Received November 08 2012)

(Revised January 16 2013)

(Accepted January 31 2013)

(Online publication March 27 2013)

Key words

  • Anxiety;
  • delusions;
  • paranoia;
  • psychosis;
  • PTSD


c1 Address for correspondence: D. Freeman, Ph.D., Oxford Cognitive Approaches to Psychosis, University Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford OX3 7JX, UK. (Email: