Concerns about a systematic review of mediators of PTSD treatments: A commentary on Alpert and colleagues (2023)

The systematic review by Alpert and colleagues (Clinical Psychology Reviews, https://doi.org/10.1016/j.cpr.2023.102300) suggests methodological standards for mediation analysis and evaluates the evidence for mediation of PTSD treatment effects in published research. Although the article articulates important methodological guidelines related to timing of treatment, mediator, and outcome, it fails to incorporate the insights of causal mediation analysis into the methodological standards. In particular, the systematic review does not recognize the limitations of using time, rather than PTSD treatment type, in mediation analyses and does not include an assessment of the potential impact of uncontrolled confounding between the mediator and the outcome in the included studies. The conclusions about mediators of PTSD treatments from this systematic review should be considered carefully.