Using neurobiological measures to predict and assess treatment outcome of psychotherapy in posttraumatic stress disorder: systematic review

Background: Trauma-focused cognitive-behavioral therapy (TF-CBT) and eye movement desensitization and reprocessing (EMDR) are effective treatments for posttraumatic stress disorder. However, little is known about their neurobiological effects. The usefulness of neurobiological measures to predict the treatment outcome of psychotherapy also has yet to be determined. Methods: Systematic review of randomized controlled trials (RCTs) focused on neurobiological treatment effects of TF-CBT or EMDR and trials with neurobiological measures as predictors of treatment response. Results: We included 23 publications reporting on 16 separate trials. TF-CBT was compared with a waitlist in most trials. TF-CBT was associated with a decrease in heart rate and blood pressure and changes in activity but not in volume of frontal brain structures and the amygdala. Neurobiological changes correlated with changes in symptom severity. EMDR was only tested against other active treatments in included trials. We did not find a difference in neurobiological treatment effects between EMDR and other treatments. Publications on neurobiological predictors of treatment response showed ambiguous results. Conclusion: TF-CBT was associated with a reduction of physiological reactivity. There is some preliminary evidence that TF-CBT influences brain regions involved in fear conditioning, extinction learning and possibly working memory and attention regulation; however, these effects could be nonspecific psychotherapeutic effects. Future trials should use paradigms aimed specifically at these brain regions and physiological reactivity. There are concerns regarding the risk of bias in some of the RCTs, indicating that methodologically more rigorous trials are required. Trials with neurobiological measures as predictors of treatment outcome render insufficient results to be useful in clinical practice.