Gerger, H., Munder, T., Gemperli, E., Nuesch, E., Trelle, S., Juni, P., & Barth, J. (2014). Integrating fragmented evidence by network meta-analysis. Relative effectiveness of psychological interventions for adults with post-traumatic stress disorder. Psychological Medicine, doi:10.1017/S0033291714000853.
Gerger and colleagues conducted a network meta-analysis to summarize the evidence on the effectiveness of psychological interventions for post-traumatic stress disorder (PTSD). Psychological trauma is common in the population (between 40% and 90% lifetime prevalence), and many people develop symptoms following the trauma that may turn into PTSD. For example people may re-experience the traumatic event, avoid stimuli related to the traumatic event, or experience increased arousal. Even those who do not meet DSM-IV criteria for PTSD may still have severe impairment and chronic symptoms. Specific interventions for PTSD include exposure to trauma related stimuli or working through cognitions related to the trauma. Non-specific interventions might include supportive therapy or relaxation treatments. As I mentioned in previous blogs, meta-analyses are the best way to summarize the evidence of existing research in order to make clinical decisions about practice. Meta-analyses allow us to pool the effect sizes from individual studies of many patients into an average effect. This method provides the most reliable estimates of the effects of treatments – no single study can be as reliable. Network meta-analysis is a relatively new method that not only allows one to accumulate results from trials that directly compare the same two treatments, but it also allows indirect comparisons of a treatment and another treatment that was tested in a different study. In their network meta-analysis, Gerger and colleagues included 66 studies representing 4,196 patients. Specific treatments included cognitive behavioral therapies (CBT), eye movement disensitization and reprocessing (EMDR), and exposure based therapy (ET). Non-specific interventions included stress management (SM) and supportive therapy (ST). The positive effect of specific interventions (CBT, EMDR, and ET) compared to a wait-list control was large. The positive effect of non-specific interventions (SM, ST) compared to a wait-list control was moderate. There were no differences in effectiveness among the psychological interventions, except EMDR outperformed ST. However, this difference disappeared when only the large scale trials were considered (results from large scale trials tend to be more reliable). Patients with a formal diagnosis of PTSD appear to benefit more from psychological interventions than those with sub-clinical PTSD, though both groups improved.
Different specific interventions for PTSD (CBT, EMDR, ET) appear to have similar positive benefits with large effects. Indirect interventions show moderately positive effects. Supportive therapy (ST) may be beneficial, but the authors indicated that it is too early to conclude that ST is as effective as direct specific interventions. All patients benefit from psychological interventions, though those with more severe symptoms stand to gain the most. Given the similar outcomes of interventions and the number of effective interventions, researchers are now arguing that factors such as access, acceptability, and patient preference should influence the choice of treatment.