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Virtual reality in the treatment of persecutory delusions: Randomised controlled experimental study testing how to reduce delusional conviction

  • Daniel Freeman (a1), Jonathan Bradley (a1), Angus Antley (a2), Emilie Bourke (a1), Natalie DeWeever (a1), Nicole Evans (a1), Emma Černis (a1), Bryony Sheaves (a1), Felicity Waite (a1), Graham Dunn (a3), Mel Slater (a4) and David M. Clark (a5)...
Abstract
Background

Persecutory delusions may be unfounded threat beliefs maintained by safety-seeking behaviours that prevent disconfirmatory evidence being successfully processed. Use of virtual reality could facilitate new learning.

Aims

To test the hypothesis that enabling patients to test the threat predictions of persecutory delusions in virtual reality social environments with the dropping of safety-seeking behaviours (virtual reality cognitive therapy) would lead to greater delusion reduction than exposure alone (virtual reality exposure).

Method

Conviction in delusions and distress in a real-world situation were assessed in 30 patients with persecutory delusions. Patients were then randomised to virtual reality cognitive therapy or virtual reality exposure, both with 30 min in graded virtual reality social environments. Delusion conviction and real-world distress were then reassessed.

Results

In comparison with exposure, virtual reality cognitive therapy led to large reductions in delusional conviction (reduction 22.0%, P = 0.024, Cohen's d = 1.3) and real-world distress (reduction 19.6%, P = 0.020, Cohen's d = 0.8).

Conclusion

Cognitive therapy using virtual reality could prove highly effective in treating delusions.

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Copyright
Corresponding author
Professor Daniel Freeman, Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford OX3 7JX, UK. Email: daniel.freeman@psych.ox.ac.uk
Footnotes
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Declaration of interest

None.

Footnotes
References
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1 Freeman, D, Garety, PA, Kuipers, E, Fowler, D, Bebbington, PE. A cognitive model of persecutory delusions. Br J Clin Psychol 2002; 41: 331–47.
2 Salkovskis, PM. The importance of behaviour in the maintenance of anxiety and panic: a cognitive account. Behav Psychother 1991; 19: 619.
3 Wells, A, Clark, DM, Salkovskis, P, Ludgate, J, Hackmann, A, Gelder, M. Social phobia: the role of in-situation safety behaviours in maintaining anxiety and negative beliefs. Behav Ther 1995; 26: 153–61.
4 Salkovskis, PM, Clark, DM, Hackmann, A, Wells, A, Gelder, MG. An experimental investigation of the role of safety-seeking behaviours in the maintenance of panic disorder with agoraphobia. Behav Res Ther 1999; 37: 559–74.
5 Sloan, T, Telch, M. The effects of safety-seeking behaviour and guided threat reappraisal on fear reduction during exposure: an experimental investigation. Behav Res Ther 2002; 40: 235–51.
6 Kim, E-J. The effect of the decreased safety behaviors on anxiety and negative thoughts in social phobics. Anxiety Disord 2005; 19: 6986.
7 McManus, F, Sacadura, C, Clark, DM. Why social anxiety persists: an experimental investigation of the role of safety behaviours as a maintaining factor. J Behav Ther Exp Psychiatry 2008; 39: 147–61.
8 Freeman, D, Garety, PA, Kuipers, E. Persecutory delusions: developing the understanding of belief maintenance and emotional distress. Psychol Med 2001; 31: 1293–306.
9 Freeman, D, Garety, P, Kuipers, E, Fowler, D, Bebbington, PE, Dunn, G. Acting on persecutory delusions: the importance of safety seeking. Behav Res Ther 2007; 45: 8999.
10 Freeman, D. Studying and treating schizophrenia using virtual reality (VR): a new paradigm. Schizophr Bull 2008; 34: 605–10.
11 Sanchez-Vives, M, Slater, M. From presence to consciousness through virtual reality. Nat Rev Neurosci 2005; 6: 332–9.
12 Slater, M, Rovira, A, Southern, R, Swapp, D, Zhang, J, Campbell, C, et al. Bystander responses to a violent incident in an immersive virtual environment. PLoS One 2013; 8: e52766.
13 Powers, M, Emmelkamp, P. Virtual reality therapy for anxiety disorders. J Anxiety Disord 2008; 22: 561–9.
14 Freeman, D, Garety, PA. Comments on the content of persecutory delusions: does the definition need clarification? Br J Clin Psychol 2000; 39: 407–14.
15 Kay, SR. Positive and Negative Syndromes in Schizophrenia. Brunner, 1991.
16 Haddock, G, McCarron, J, Tarrier, N, Faragher, EB. Scales to measure dimensions of hallucinations and delusions: the psychotic symptom rating scales (PSYRATS). Psychol Med 29; 1999; 879–89.
17 Beck, AT, Epstein, N, Brown, G, Steer, R. An inventory for measuring clinical anxiety: psychometric properties. J Consult Clin Psychol 1988; 56: 893–7.
18 Beck, AT, Steer, RA, Brown, GK. BDI-II Manual. The Psychological Corporation, 1996.
19 Elashoff, JD. nQuery Advisor 4.0 User's Guide. Dixon Associates, 2000.
20 Freeman, D. Persecutory delusions: a cognitive perspective on understanding and treatment. Lancet Psychiatry, in press.
21 Clark, D, Ehlers, A, Hackmann, A, McManus, F, Fennell, M, Grey, N, et al. Cognitive therapy versus exposure and applied relaxation in social phobia. J Consult Clin Psychol 2006; 74: 568–78.
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  • EISSN: 1472-1465
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Virtual reality in the treatment of persecutory delusions: Randomised controlled experimental study testing how to reduce delusional conviction

  • Daniel Freeman (a1), Jonathan Bradley (a1), Angus Antley (a2), Emilie Bourke (a1), Natalie DeWeever (a1), Nicole Evans (a1), Emma Černis (a1), Bryony Sheaves (a1), Felicity Waite (a1), Graham Dunn (a3), Mel Slater (a4) and David M. Clark (a5)...
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eLetters

Remarks on the evidence base and readability of Freeman et al. July 2016

John L Fresen, Statistician, IT Services, University of Oxford
04 May 2017

We commend Freeman et al. (2016) for their innovative research using virtual reality in the treatment of persecutory delusions. The rather ‘soft’ finding − probably valid, but hardly surprising – is: “Cognitive therapy, using a virtual reality setting, could prove highly effective in treating delusions”.

We have concerns about the evidence base of the study, i.e. the design, the data, the sample and the statistical methodology. Each of these concerns interrogates the validity and reproducibility of the study. See MacNutt (2014) for a discussion on reproducibility. See Gardenier and Resnik (2002) for a discussion on the misuse of statistics.

First, the sample size is extremely small – a total of 30 participants. The consequences of this include overestimates of effect size and low reproducibility of results.

Second, 27 of the 30 participants were unemployed. There is little point to any research if one cannot extrapolate from one’s sample to some broader reference population. For this, the sample should mimic the population in important ways. However, there is no discussion about the sampling, or the reference population to which extrapolation might be extended.

Third, neither the patients nor the researchers were masked to the randomisation allocations. This surely, is a fundamental flaw of the experiment. A double-blind experiment should be used to ensure impartiality, and avoid bias, such as, for example, the Hawthorne effect. See for example McCarney et al. (2007).

Fourth, the main outcomes – comparing the delusional conviction of the two groups at the beginning and end of testing, as well as their distress, were tested using ANCOVA. But, in the last paragraph on page 3 they say: “For ratings of conviction in paranoia, a gradual reduction across the scenarios for the threat belief testing group can be seen, whereas the conviction scores remain stable in the exposure group”. This suggests that the two groups diverge over time, having different slopes, rather than the assumed homogeneous slopes in the ANCOVA model.



Fifth, the term “repeated measures mixed model” covers a wide range of possible models, and leads one to expect a single model incorporating the repeated measures and random effects, not ten models as are presented in the supplement. Further, none of the models are clearly articulated in mathematical form.

Sixth, there are no graphs to display the data or statistical results. Tay et al. (2016) propose the use of graphical descriptives to enhance research rigour, especially in psychology.

It appears that the article is written on two levels. The introduction and method sections, describing participants, design and virtual reality, are clear and lucid. By contrast, the evidence base of the article, discussing the data, models, analysis and results, is almost unintelligible. Further, the small sample size, sampling bias, lack of randomization masking, lack of model specification, and lack of statistical graphics, seriously undermine the study.

The phrase “evidence based research” has become popular in psychology. Thus, it is incumbent on readers, authors and journal editors to ‘raise the bar’ and demand higher standards on the evidence base of research studies.

References

Freeman, D., Bradley, J., Antley, A., Bourke, E., De Weever, N., Evans, N., Cernis, E., Sheaves, B., Waite, F., Dunn, G., Slater, M. & Clark, D.M. (2016) Virtual reality in the treatment of persecutory delusions: randomised controlled experimental study testing how to reduce delusional conviction. The British Journal of Psychiatry, 1–6. doi: 10.1192/bjp.bp.115.176438.

Gardenier, J. S. and Resnik, D. B. (2002) The Misuse of Statistics: Concepts, Tools, and a Research Agenda, Accountability in Research, 9: 65–74, 2002 Copyright © 2002, DOI: 10.1080/08989620290009521

McCarney, R., Warner, J., Iliffe, S., van Haselen, R., Griffin, M., & Fisher, P. (2007). The Hawthorne Effect: a randomised, controlled trial. BMC Medical Research Methodology, 7, 30. http://doi.org/10.1186/1471-2288-7-30

McNutt, M. (2014). Reproducibility. Science, 343, (6168), 229. doi: 10.1126/science.1250475.

Tay, L., Parrigon S., Huang, Q., & LeBreton, J.M. (2016). Graphical descriptives: A way to improve data transparency and methodological rigor in psychology. Perspectives on Psychological Science, 11(5):692 –701, doi: 10.1177/1745691616663875.

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