Individual Patient Data Meta-Analysis for Posttraumatic Stress Disorder
Authors:   , Wright Simonne Lesley 
Published: November 2024

Posttraumatic stress disorder (PTSD) is a mental health condition arising from exposure to traumatic events. Despite advancements in treatment, challenges persist in identifying which therapeutic approaches are most effective for specific patient subgroups. This research was a collaborative effort between Stellenbosch University and Vrije Universiteit to identify demographic, clinical, and psychological predictors and moderators of PTSD treatment outcomes.
In the first study, I conducted an examination of the efficacy of eye movement desensitization and reprocessing (EMDR) and other psychological treatments using IPD meta-analyses across eight studies (n = 346). Findings revealed no significant differences in PTSD symptom severity (β = −0.24), treatment response (β = 0.86), remission rates (β = 1.05), and study dropout (β = −0.25) between EMDR and other psychological treatments. Moderator analyses found unemployed participants had higher PTSD symptom severity post-treatment than employed (β = 0.80), and males were more likely to drop out than females (β = 0.23) receiving EMDR.
In the second study, I conducted a systematic review and IPD meta-analyses to evaluate the efficacy of 12 studies comparing CBT-TF to inactive treatments (n = 625), as well as 11 studies comparing CBT-TF to active treatments (n =706). The analysis focused on identifying participant-level factors that might moderate the effectiveness of CBT-TF against both inactive and active comparison groups independently. Results indicated participants receiving CBT-TF had significantly lower PTSD symptom severity (β = −0.78) and higher PTSD remission (OR = 2.34) post-intervention than inactive comparison groups such as waiting list control, treatment-as-usual, and CBT for substance use disorder. When comparing CBT-TF to inactive treatments, moderator analysis found that divorced participants who received CBT-TF had greater PTSD symptoms post-intervention than participants who were single, cohabitating, or married and received CBT-TF (β = 0.93). Furthermore, no significant difference in PTSD symptom severity (β = 0.02) and PTSD remission (OR = 0.53) was found between participants receiving CBT-TF and the active comparison groups post-intervention. In the active treatment comparison, moderator analysis found that participants taking psychotropic medication had lower PTSD symptoms than those not taking psychotropic medication following CBT-TF (β = −0.39).
In the third study, I investigated predictors of study dropout in CBT-TF in 28 CBT-TF intervention groups from 25 studies (n = 823). Results indicated that overall, 221 (27%) of the 823 dropped out. Of 581 civilians, 133 (23%) dropped out, as did 75 (42%) of 178 military personnel/veterans. Bivariate and multivariate analyses indicated that military personnel/ veterans (RR 2.37) had a significantly greater risk of dropout than civilians. Furthermore, the chance of dropping out significantly decreased with advancing age (continuous; RR 0.98).
In the last study, I first examined dropout rates between drug and placebo groups through a conventional meta-analysis of 43 RCTs (n = 4,829). Results indicated the difference was not statistically significant (RR = 0.92). Subgroup analyses and meta-regression indicated that dropout rates were not associated with drug class, dosing regimen, population characteristics, study duration, or gender composition. Additionally, I explored participant-level predictors of dropout across drug, placebo, and combined groups, using data pooled from three RCTs (n = 246). Results indicated no significant difference in dropout rates between the drug and placebo groups (p = .617). Gender emerged as a significant predictor of study dropout in the drug group analyses only, with males showing higher dropout rates (p = .046). However, when baseline PTSD symptom severity was controlled for, gender was no longer a statistically significant (p = .051).
This research contributes to the growing body of evidence needed to enhance global PTSD treatment practices, with a specific focus on addressing high-risk subgroups and improving patient outcomes.