Imagery rescripting (ImRs) is an experiential therapy technique used to change the content and meaning of intrusive imagery in post-traumatic stress disorder (PTSD) by imagining alternative endings to traumatic events. There is growing evidence that ImRs is an effective treatment for PTSD; however, little is known about how it brings about change.

This study aimed to explore the role of mental simulation as a candidate mechanism of action in ImRs, and, specifically, whether well-simulated imagery rescripts are associated with greater change in symptom severity during ImRs.

Using a single-case experimental design, seven participants receiving cognitive therapy for PTSD were assessed before, during and after sessions of imagery rescripting for one intrusive image. Participants completed continuous symptom severity measures. Sessions were recorded, then coded for goodness of simulation (GOS) as well as additional factors (e.g. rescript believability, vividness).

Participants were divided into high- and low-responders and coding was compared across groups. Correlational analyses were supported by descriptive analysis of individual sessions. High-responders’ rescripts tended to be rated as well-simulated compared with those of low-responders. Specific factors (e.g. intensity of thoughts/emotions related to original and new imagery elements, level of cognitive and emotional shift and belief in the resultant rescript) were also associated with reductions in symptom severity.

There was tentative evidence that well-simulated rescripted images tended to be associated with greater reductions in symptom severity of the target image. Clinical implications and avenues for further research are discussed.

Post-traumatic stress disorder (PTSD) is a potentially chronic and disabling disorder affecting a significant minority of people exposed to trauma. Various psychological treatments have been shown to be effective, but their relative effects are not well established.

We undertook a systematic review and network meta-analyses of psychological interventions for adults with PTSD. Outcomes included PTSD symptom change scores post-treatment and at 1–4-month follow-up, and remission post-treatment.

We included 90 trials, 6560 individuals and 22 interventions. Evidence was of moderate-to-low quality. Eye movement desensitisation and reprocessing (EMDR) [standardised mean difference (SMD) −2.07; 95% credible interval (CrI) −2.70 to −1.44], combined somatic/cognitive therapies (SMD −1.69; 95% CrI −2.66 to −0.73), trauma-focused cognitive behavioural therapy (TF-CBT) (SMD −1.46; 95% CrI −1.87 to −1.05) and self-help with support (SMD −1.46; 95% CrI −2.33 to −0.59) appeared to be most effective at reducing PTSD symptoms post-treatment v. waitlist, followed by non-TF-CBT, TF-CBT combined with a selective serotonin reuptake inhibitor (SSRI), SSRIs, self-help without support and counselling. EMDR and TF-CBT showed sustained effects at 1–4-month follow-up. EMDR, TF-CBT, self-help with support and counselling improved remission rates post-treatment. Results for other interventions were either inconclusive or based on limited evidence.

EMDR and TF-CBT appear to be most effective at reducing symptoms and improving remission rates in adults with PTSD. They are also effective at sustaining symptom improvements beyond treatment endpoint. Further research needs to explore the long-term comparative effectiveness of psychological therapies for adults with PTSD and also the impact of severity and complexity of PTSD on treatment outcomes.