Exposure-Based Writing Therapies for Subthreshold and Clinical Posttraumatic Stress Disorder: A Systematic Review and Meta-Analysis

We undertook a systematic review to assess the efficacy of exposure-based writing therapies (WTs) for trauma-exposed adults with subthreshold or clinical levels of posttraumatic stress disorder. Four databases (PsycINFO, Medline, Wiley Online, PILOTS) were searched for randomized controlled trials (RCTs) of exposure-based WTs. A total of 13 RCTs that reported on results from 17 WT versus control comparisons were included. The primary outcomes were posttraumatic stress symptom severity at posttreatment and/or clinical response. An overall unclear or high risk of bias was identified in 84.6% of studies. In comparison to both waitlist k = 3, Hedges’ g = −0.97, 95% CI [-1.20, -0.73], and placebo writing conditions, k = 9, Hedges’ g = −0.48, 95% CI [-0.87, -0.08], WTs were more beneficial to participants. There was no evidence of a difference between WTs that were longer in duration compared to other psychotherapy, k = 2; pooled OR = 1.42; 95% CI [0.83, 2.43]. These findings indicate that exposure-based WTs are effective when compared to waitlist and placebo writing control conditions. The evidence needs to be considered in the context of the modest number of studies conducted to date, the high methodological heterogeneity between the studies, and the high or unclear risk of bias across many studies. Further research is needed to increase the evidence base regarding the efficacy of WTs for posttraumatic stress. Future research should also measure the mediators and predictors of outcomes to further develop protocols and understand which variants of WTs work for different populations or individuals.