The findings of this systematic review suggest that between 14% and 47% of people with psychosis might experience psychosis-related PTSD. Depression was most commonly associated with psychosis-related PTSD. Other factors that were associated in at least one study were: symptom-related (severity of psychosis, positive symptoms, and general psychopathology); treatment-related (restraint, length of admission, number of traumatic hospital events); childhood trauma and childhood trauma-related PTSD; reactions to the trauma (maladaptive coping, reluctance to talk, actual self-disclosure); and other individual-level factors (experiences of shame, anxious attachment).
The number of studies included in this review (six) was considerably smaller than in previous reviews, which included 24 (14) and 13 (15) studies, many of which were published before 2011. We did not find, as we had expected, that more studies had been published since 2011 in line with the increasing interest in trauma in mental health research. We also found few studies clearly looking beyond the first episode; most of the studies were set in early psychosis services and/or did not describe their sample with sufficient detail. Due to this, we were unable to examine psychosis-related PTSD across the course of psychosis as we had planned.
The prevalence rates we found were similar to the rates of 11-67% reported by Berry et al. (2013) (14) and the pooled prevalence estimates of 30% (PTSD diagnosis) and 42% (PTSD symptoms) reported by Rodrigues and Anderson (2017) (15). Our review and both previous reviews found wide variations in reported prevalence rates. In our narrative synthesis we examined differences in the conceptualisation, definition and assessment of psychosis-related PTSD between the included studies and it is likely that these factors can provide some explanation for variations in prevalence rates across all three reviews (20). Other factors such as differences in participant populations, in the amount of cumulative exposure to traumatic psychosis and in service provision experienced, may also account for the wide variations in prevalence rates between studies across all three reviews. Similar to our findings, both previous reviews listed trauma history, psychosis severity and depression as possible related factors. They also noted that sample sizes were possibly too small to detect associations and reliably estimate prevalence.
The findings of our review largely corroborate the findings in the previous review by Berry et al (2013) (14). However, the Berry et al (2013) (14) review was limited in that it was not systematic. As our review used systematic methodology it provides more robust evidence for prevalence rates and factors associated with psychosis-related PTSD. Additionally due to the rigorous systematic methods we employed, we can say with reasonable certainty that the low number of papers retrieved reflects the lack of recent research, rather than the possibility that papers were missed. Importantly, our review has highlighted that there have been few studies conducted on this topic over the past decade, despite appeals that further research is required. For example, the authors of the earlier review stated that future research should use sensitive measures of trauma, separate out symptom and treatment-related PTSD, and that psychological processes should be investigated. The present review has found that largely, these recommendations have not yet been met. Some studies have separated out symptom and treatment-related PTSD, but this is not consistent. Some of the papers elicited in our review focussed on psychological processes which were hypothesised to be important in the development of psychosis-related PTSD, but most did not.
The review by Rodrigues and Anderson (2017) (15) was systematic and used meta-analysis; however, they too were limited by a small number of studies to analyse (the subgroups included in meta-analyses were made up of 8 and 4 studies). This previous review was solely focussed on first episode psychosis so it has not hitherto been known whether the first episode of psychosis is more or less traumatic than subsequent episodes. The present review had a broader scope by including studies across the course of psychosis and as a result we retrieved studies not included in the review by Rodrigues and Anderson (2017) (15). Those additional studies provided data that allowed us to look closely at theories underpinning the development of psychosis-related PTSD (e.g. attachment theory; 25) and suggested how separate experiences may lead to PTSD symptoms (e.g. by separating delusions and hallucinations; 24).
Strengths and limitations of included studies
Due to the cross-sectional designs, we cannot infer causation of associated factors. Prospective research is required and is possible. One of our excluded studies recruited patients during the acute stage of psychosis and then followed them up 18 months later, allowing them to investigate whether psychosis-related factors were predictors of PTSD (36). Their measurement of PTSD was not specific to psychosis-related events so this study had to be excluded, however its prospective methodology is noteworthy. Many included studies did not adjust for plausible confounders, such as non-psychosis-related PTSD. Most of the sample sizes were small and limited to one service. Studies which reported statistically significant associations (27) had very large confidence intervals indicating high variance within the samples. With sample sizes this small it is difficult to generalise the findings.
A limitation in this field is a lack of agreement whether trauma related to symptoms and trauma related to treatment are both ‘psychosis-related’ and whether distinctions between these should be made when collecting data. Differences between studies on how the same measurement tool was used might have elicited different rates of PTSD, and this variability between studies on the concept of psychosis-related PTSD presents complications in comparing prevalence rates and associated factors between different studies.
The measurement tools used were generally psychometrically robust and validated, and the questionnaires had been reliably used with psychosis populations. The use of a clinician-administered scale in one study, the CAPS, is positive as this is considered the gold-standard for measuring PTSD. However, interrater reliability was not assessed, and the CAPS was translated into Tunisian-Arabic for this study but was not validated in that cultural context. Most of the studies included did not sufficiently describe their non-participation rate; individuals who chose not to participate in research about trauma might have declined precisely because they have PTSD, therefore there is a risk of sampling bias across the studies.
Potentially relevant factors were not investigated for associations with psychosis-related PTSD. Firstly, ethnicity: research suggests that people from black and minority ethnic (BME) backgrounds are considerably more likely to be diagnosed with psychosis (37) and to receive coercive treatment (38) than other ethnicities. They could therefore be particularly vulnerable to traumatic psychosis-related experiences. However, none of the included studies assessed for associations between ethnicity and psychosis-related PTSD.
Treatment-related factors were somewhat neglected across the studies and only one study assessed correlations with involuntary hospitalisation and restraint (28). Coercive practices are potentially modifiable but the paucity of research into treatment factors limits understanding of their traumatic nature and potentially reductions in their use.
Some known risk factors for PTSD were not assessed in the included studies. Predictors of PTSD are reported to include perceived threat, intense emotions and dissociation during the traumatic event, and low perceived social support after the event (12, 13). Perceived threat was partly investigated by Abdelghaffar et al. (2018) (28) who assessed perception of threat from other patients and care providers. Pietruch and Jobson (2012) (23) investigated disclosure of trauma, which is one aspect of social support; however, social support might protect against PTSD in more ways than encouraging people to talk about their trauma. Intense emotions and dissociation during psychosis were not assessed in the included studies.
Strengths and limitations of the review
Our review was restricted to papers published from 2011 onwards which resulted in only a small number of studies being retrieved. However, this allowed us to provide an updated evidence review and to look more closely at the extent and drivers of psychosis-related PTSD in a modern healthcare context. Our inclusion criteria resulted in the exclusion of a doctoral thesis due to non-peer review, and a paper written in French as we were unable to translate it. Both of these may have contributed to the findings in this review had they been included. However, our search strategy was broad, so it is unlikely we missed relevant papers; we searched five databases, used over-inclusive search terms, and a second reviewer assisted with the screening of the search output.
The small number of included studies prevented the ability to carry out analyses of subgroups as planned a priori in the PROSPERO protocol. However, finding only six additional studies than the previous reviews (14, 15) reflects the lack of research published in the field since 2011 despite recommendations for further research, rather than being a limitation of this review per se. This review has highlighted that further studies of prevalence and associated factors are required, with distinctions made between FEP and multiple-episode psychosis, and that greater clarity and consistency in how psychosis-related PTSD should be defined and assessed is necessary to reliably combine results from multiple studies.
We adapted a quality assessment tool because we could not find a more appropriate, validated tool for this review. This could have been further adapted to include some factors specifically relevant to the assessment of PTSD, such as whether sufficient amount of time had lapsed since traumatic event for a diagnosis of PTSD (20). However, the tool we used was utilised in a similar adapted form in previous studies (15). The adaptation of the tool to fit our criteria was assisted by a second reviewer independently, reducing risk of bias. The adaptation resulted in the removal of all follow-up criteria due to irrelevance to the research question.
We included a study (24) which did not report an overall prevalence rate for psychosis-related PTSD, but instead separate rates for different psychosis-related events (e.g. delusions, hallucinations, involuntary hospitalisation). These figures could not be directly compared with prevalence rates from other studies. However, we decided to include this study as it does provide relevant data on people meeting PTSD criteria based on their psychosis experience.
This review built upon previous reviews (14, 15) by exploring the underlying theories of some of the associations between psychosis and related PTSD (e.g. attachment theory, trauma sensitization theory, theories of shame and disclosure of trauma). This can hopefully support the future development of a model of the processes by which psychosis-related PTSD might occur.
Implications in research, theory and practice
Studies with prospective designs and larger sample sizes from a wider variety of settings are needed. Research should distinguish between people who have had one or multiple episodes, to investigate a potential cumulative effect of trauma from psychosis, and assess more potential risk factors, such as various treatment factors, social support, dissociation, intense emotions and ethnicity.
The wide variation in reported prevalence rates for psychosis-related PTSD is hard to interpret. Moreover, the rates of psychosis-related PTSD reported in some studies in our review are higher than rates of PTSD from any cause among people with psychosis reported in other recent studies, which did not distinguish rates of psychosis-related PTSD and were therefore not included in our review (39, 40). We need more studies in a variety of settings and clinical populations, and more consensuses on gold-standard PTSD measures, to be able to understand how much in the variance of psychosis-related PTSD may be an artefact of inconsistent measurement approaches, and how much reflects genuine variation in clinical morbidity.
Some existing psychosocial theories might explain mechanisms underlying psychosis-related PTSD and could in the future form part of an integrated model of psychosis-related PTSD; however before this is possible there needs to be exploration of societal, environmental, cultural, and neurobiological factors.
Currently, an episode of psychosis does not fulfil criterion A in the DSM-V for a traumatic event which requires “exposure to actual or threatened death, serious injury, or sexual violence (41). It has been argued that this criterion should be expanded to include internally experienced events such as psychosis as it is the perception of threat that is necessary for PTSD (42). Proposals for the ICD-11 will allow flexibility in the judgement of either an objective or subjective traumatic event (43). In our review, the rates of people meeting PTSD symptom criteria following the experience of psychosis provides further support for the inclusion of subjective threat as a qualifying traumatic event that satisfies criterion A in the DSM-V classification.
Rates of psychosis-related PTSD do not appear to have reduced since 2011. The ongoing development of TIC has the potential to reduce traumatic experiences associated with psychosis, such as the use of coercive practices (16). However, coercive practices appear to be increasing in the UK (44), particularly for people with psychosis (45). In addition to reduced distressing treatment practices, TIC involves services recognizing that the experience of psychosis can be traumatic, screening patients for PTSD, and offering evidence-based treatments (which, NICE guidelines stipulate should commence promptly, 46). Well implemented TIC may not directly lead to a reduction in reported rates of psychosis-related PTSD in practice, as it may conversely lead to an increase in case identification, but it would be expected that rates would decline in cross-sectional studies. It is currently not clear to what extent TIC is being delivered in clinical services. It remains crucial that TIC be developed and implemented and that services recognise the traumatic experience of psychosis and achieve early identification of psychosis-related PTSD followed by effective treatment.