Elsevier

Schizophrenia Research

Volume 195, May 2018, Pages 13-22
Schizophrenia Research

Do trauma-focussed psychological interventions have an effect on psychotic symptoms? A systematic review and meta-analysis

https://doi.org/10.1016/j.schres.2017.08.037Get rights and content

Abstract

There is growing recognition of the relationship between trauma, posttraumatic stress disorder (PTSD) and psychosis. There may be overlaps in causal mechanisms involved in the development of PTSD and psychosis following traumatic or adverse events. Trauma-focussed treatments found to be effective in treating PTSD may therefore represent a new direction in the psychological treatment of psychosis. This systematic review examined the literature on trauma-focussed treatments conducted with people with schizophrenia spectrum or psychotic disorders to determine effects on psychotic symptoms. Secondary outcomes were symptoms of PTSD, depression and anxiety. Twenty-five studies were included in the review, with 12 being included in the meta-analysis. Trauma-focussed treatments had a small, significant effect (g = 0.31, CI [0.55, 0.06]) on positive symptoms immediately post-treatment, but the significance and magnitude of this effect was not maintained at follow-up (g = 0.18, CI [0.42, − 0.06]). Trauma-focussed treatments also had a small effect on delusions at both post-treatment (g = 0.37, CI [0.87, − 0.12]) and follow-up (g = 0.38, CI [0.67, 0.10]), but this only reached significance at follow-up. Effects on hallucinations and negative symptoms were small and non-significant. Effects on PTSD symptoms were also small (post-treatment g = 0.21, CI [0.70, − 0.27], follow up g = 0.31, CI [0.62, 0.00]) and only met significance at follow-up. No significant effects were found on symptoms of depression and anxiety. Results show promising effects of trauma-focussed treatments for the positive symptoms of psychosis, however further studies developing and evaluating trauma-focussed treatments for trauma-related psychotic symptoms are needed.

Introduction

There is mounting evidence that exposure to traumatic or adverse experiences in childhood represents a significant risk factor in the development of psychosis (Bendall et al., 2008, Read et al., 2001, Varese et al., 2012) and there is thematic correspondence between the content of psychotic experiences and significant past life events (Corstens and Longden, 2013, Hardy et al., 2005, McCarthy-Jones et al., 2014). There is also compelling evidence to suggest a relationship between posttraumatic stress disorder (PTSD, arguably the ‘hallmark’ disorder caused by traumatic events) and psychosis, including high rates of comorbidity (Sareen et al., 2005) and PTSD being a risk factor for the development of psychosis (Okkels et al., 2017).

This relationship suggests similar mechanisms could be involved in psychotic experiences and symptoms of PTSD (Morrison et al., 2003). For example, it has been proposed that auditory hallucinations are a type of posttraumatic intrusion, contributed to by contextual processing difficulties (Hardy, 2017, Steel et al., 2005). Additionally, dissociation (Moskowitz and Corstens, 2007) and negative posttraumatic beliefs (Gracie et al., 2007) have been implicated in the development of auditory hallucinations. Similar psychological mechanisms are also implicated in the development of delusional experiences and PTSD symptoms following a traumatic event (Freeman et al., 2013), whilst negative symptoms have been conceptualized as manifestations of trauma-related avoidance (McGorry, 1991).

Trauma-focussed (TF) interventions are effective in treating PTSD (Bisson et al., 2007). Given potential mechanistic overlaps between PTSD and psychosis TF treatments represent a new direction in treatment development for psychosis. This aligns with mental health service-user calls for therapeutic approaches that consider psychosis in the context of past life experiences (Corstens et al., 2014). Recently, researchers have begun to apply TF treatments to comorbid PTSD and other trauma-related symptoms in people with psychotic disorders. Whilst evidence remains too limited for a Cochrane review to draw any meaningful conclusions (Sin et al., 2017), two recent reviews have concluded that TF treatments can be used safely and effectively reduce PTSD symptoms in this population (Sin and Spain, 2016, Swan et al., 2017). Emerging data also suggests that TF treatments may have an impact on psychotic symptoms, but this is yet to be systematically synthesized across studies. We examined the literature on TF treatments conducted within psychosis populations to determine whether these interventions have an effect on psychotic symptoms.

Section snippets

Methods

The review was prospectively registered with the International Prospective Register of Systematic Reviews (PROSPERO), protocol no: CRD42016035827 and is reported in accordance with PRISMA guidelines.

Results

The database search yielded 4399 records. Once duplicates were removed, 3236 records were screened on titles and abstracts. Forty-one full text records were assessed. An additional two ‘in press’ studies were identified through contact with the authors (de Bont et al., 2016, Steel et al., 2016). Twenty-five articles were included in the final review. Fig. 1 displays the PRISMA flow-chart of the selection process.

Primary outcomes: do TF therapies have an effect on the symptoms of psychosis?

The results of the meta-analysis suggest that TF treatments have a small, significant effect on the positive symptoms of psychosis immediately following treatment. The between-group effect size of 0.31 post-treatment is notable, since it is within the range of effect sizes usually reported for current best-practice CBT for psychosis when compared with TAU (Jauhar et al., 2014, van der Gaag et al., 2014, Wykes et al., 2008). However, the fact that this between-group effect was not maintained at

Contributors

RB designed the review, wrote the protocol, managed the literature searches, quality checks and analyses and led the write up of the manuscript. NT provided methodological and content advice throughout the process of the review. Author CM was a second rater in screening articles for inclusion, rating risk of bias and GRADE assessments. Authors SB and SR had input to protocol development and writing up the final manuscript. All authors contributed to and have approved the final manuscript.

Conflict of interest

The authors have no conflicts of interest to declare.

Acknowledgements

We thank all of the authors of the original studies included in the review for kindly providing the data necessary for our analysis.

Funding source declaration

The first author is funded by a Swinburne University of Technology PhD scholarship.

References (56)

  • M. Borenstein et al.

    Introduction to Meta-analysis

    (2009)
  • R.M. Brand et al.

    Can we use an interventionist-causal paradigm to untangle the relationship between trauma, PTSD and psychosis?

    Front. Psychol.

    (2017)
  • P. Calcott et al.

    Trauma Within Psychosis: Using A CBT Model for PTSD in Psychosis

    Behavioural and Cognitive Psychotherapy

    (2004)
  • D. Corstens et al.

    The origins of voices: links between life history and voice hearing in a survey of 100 cases

    Psychosis

    (2013)
  • D. Corstens et al.

    Emerging perspectives from the hearing voices movement: implications for research and practice

    Schizophr. Bull.

    (2014)
  • P.A.J.M. de Bont et al.

    Prolonged exposure and EMDR for PTSD v. a PTSD waiting-list condition: effects on symptoms of psychosis, depression and social functioning in patients with chronic psychotic disorders

    Psychol. Med.

    (2016)
  • D. Freeman et al.

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

    Psychol. Med.

    (2013)
  • C. Frueh et al.

    Exposure-based cognitive-behavioral treatment of PTSD in adults with schizophrenia or schizoaffective disorder: A pilot study

    Journal of Anxiety Disorders

    (2009)
  • A. Gracie et al.

    The association between traumatic experience, paranoia and hallucinations: a test of the predictions of psychological models

    Acta Psychiatr. Scand.

    (2007)
  • G.H. Guyatt et al.

    GRADE: an emerging consensus on rating quality of evidence and strength of recommendations

    Br. Med. J.

    (2008)
  • J.L. Hamblen et al.

    Cognitive-Behavioral Treatment for PTSD in People with Severe Mental Illness: Three Case Studies

    American Journal of Psychiatric Rehabilitation

    (2004)
  • A. Hardy

    Pathways from trauma to psychotic experiences: a theoretically informed model of posttraumatic stress in psychosis

    Front. Psychol.

    (2017)
  • A. Hardy et al.

    Healing traumatic memories in psychosis: a response to Sin and Spain (2016)

    Psychosis

    (2017)
  • A. Hardy et al.

    Trauma and hallucinatory experience in psychosis

    J. Nerv. Ment. Dis.

    (2005)
  • A. Hardy et al.

    CBT for post-traumatic stress disorder and psychosis CBT for schizophrenia: Evidence-based interventions and future directions

    (2013)
  • J.P. Higgins et al.

    The Cochrane Collaboration's tool for assessing risk of bias in randomised trials

    Br. Med. J.

    (2011)
  • S. Jauhar et al.

    Cognitive-behavioural therapy for the symptoms of schizophrenia: systematic review and meta-analysis with examination of potential bias

    Br. J. Psychiatry

    (2014)
  • I.M. Kevan et al.

    Post-traumatic stress disorder in a person with a diagnosis of schizophrenia: Examining the efficacy of psychological intervention using single N methodology

    Clinical Psychology & Psychotherapy

    (2007)
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