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 (13) and 13 (14) 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) (13) and the pooled prevalence estimates of 30% (PTSD diagnosis) and 42% (PTSD symptoms) reported by Rodrigues and Anderson (2017) (14). 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. Our review used more robust, systematic methodology than Berry et al. (2013) (13) and extended beyond the focus on FEP by Rodrigues and Anderson (2017) (14).
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 (34). 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 (25) 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 (35) and to receive coercive treatment (36) 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. 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 (11, 12). Perceived threat was partly investigated by Abdelghaffar et al. (2018) (26) who assessed perception of threat from other patients and care providers. Pietruch and Jobson (2012) (21) 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 determined that we had to exclude a doctoral thesis and a French paper which might have contributed useful findings to the review. However, our search strategy was broad so it is unlikely we missed relevant papers; we searched five relevant databases, used over-inclusive search terms, and a second reviewer assisted with the screening of the search output.
We adapted a quality assessment tool because there we could not find a more appropriate, validated tool for this review. However, a second reviewer assisted with the adaptation of this tool and with the quality assessment of the included studies, which reduced the risk of bias in our quality assessments.
We included a study (22) 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.
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 cumulative effect of trauma from psychosis, and assess more potential risk factors.
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.
Rates of psychosis-related PTSD do not appear to have reduced since 2011 despite movements towards trauma-informed care (TIC) over the past decade. TIC can reduce the use of coercive practices such as restraint and improve clinical outcomes (15). However, such practices appear to be increasing in the UK (37), particularly for people with psychosis (38). 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, 39). Recognition of the traumatic experience of psychosis and early identification of psychosis-related PTSD is important. However, our research suggests TIC may not have yet been effectively implemented in services.