Effectiveness of currently available psychotherapies for post‐traumatic stress disorder and future directions
Authors: Sonya B. Norman
Journal: World Psychiatry (2022)

Post-traumatic stress disorder (PTSD) entered the DSM just over 40 years ago. Since then, there have been more than 300 com­pleted randomized controlled trials (RCTs) of therapies for this condition, about two thirds of which have included one or more psychotherapies1. It is therefore not surprising that there is a robust evidence base of effective psychotherapies for PTSD. Trauma-focused psychotherapies, in which processing memories and emotions related to the traumatic event is a primary focus throughout the treatment, have emerged as the most effective2. Meta-analyses generally show large effect sizes for PTSD symptom reduction and high rates of loss of diagnosis or remission for these treatmentse.g.,2. Among trauma-focused psychotherapies, prolonged exposure (PE) therapy, cognitive processing therapy (CPT), cognitive therapy, and eye movement desensitization and reprocessing stand out as having the strongest evidence, because they have been studied the most, by investigators different from those who developed the treatments, and with the broadest variety of populations and comorbidities. All involve manualized protocols usually completed in about 12 sessions, most often delivered week­ly. While there have been few direct comparisons of psychotherapies and pharmacotherapies for PTSD, a meta-analysis that compared effect sizes across studies found larger effects for psychotherapies (g=1.14) than medications (g=0.42)3. There is also evidence that PTSD can be treated effectively with non-trauma-focused psychotherapies, which generally aim to improve specific skills, but effect sizes are generally smaller than for trauma-focused psychotherapies2. The availability of effective treatments has fundamentally shifted our view of PTSD from a chronic condition that we can at best hope to manage, to a condition from which it is possible to recover. While this is tremendously good news, there is still a great deal of work left to do. Not everyone with PTSD is willing or able to engage in a trauma-focused psychotherapy; dropout from PTSD treatment remains high (this is true across PTSD treatment types, in part because a hallmark symptom of PTSD is avoidance); and a number of people who engage in these treatments remain partial responders or non-responders. Ongoing work to further improve the effectiveness of psychotherapies for PTSD can be divided broadly into two categories: a) research to improve engagement in and outcomes of existing trauma-focused psychotherapies, and b) research to develop and evaluate novel psychotherapies. A delivery adaptation that is promising in terms of improving engagement in existing psychotherapies is massed treatment, that is, psychotherapy sessions offered on consecutive days or multiple times per week. This format allows patients to complete treatment in 2-4 weeks, rather than in 3-4 months as is usually the case with weekly sessions. Field studies and a small number of RCTs show treatment completion rates upward of 85%, with effectiveness as good or better than weekly therapy4. Shorter versions of treatments are another promising direction. A preliminary RCT of PE for primary care (PE-PC), a 4-session version of PE where patients meet with their therapist for 30 min instead of 90 min, showed that over 80% of participants completed the treatment. The intervention resulted in a larger reduction in PTSD severity and general distress compared with a minimal contact control, persisting at 6-month follow-up5. This version of PE is intended as part of a stepped care approach for those initiating PTSD treatment in primary care, and appears to be an adequate dose of treatment for some patients with PTSD. The common thread between massed and shorter trauma-focused psychotherapies is that patients complete treatment in a shorter amount of time, which may contribute to the higher rates of completion compared to what we usually see with PTSD treatment. Another improvement is that newer versions of PE and CPT manuals give more guidance to providers on how to help patients to process common, but sometimes challenging, non-fear based post-traumatic emotions such as guilt and shame, which may result in patients with such emotional reactions being more likely to benefit from these treatments. When more RCT results using the newer versions of these manuals become available, comparing within-group effect sizes between newer and earlier studies will shed light on whether these changes enhance treatment effec­tiveness. Regarding research to develop and evaluate novel psychotherapies for PTSD, trauma-informed guilt reduction therapy, which focuses on reducing trauma-related guilt, has promising preliminary pre-post results with a fully powered trial underway6. Written exposure therapy, which asks patients to write about their traumatic event following scripted instruction, has been found in a randomized trial to be non-inferior to CPT in reducing PTSD symptoms and to be associated with significantly fewer dropouts7. Both of these psychotherapies are brief (5 and 6 sessions respectively), which, as noted above, may facilitate higher rates of treatment completion. We still have a great deal to learn about PTSD and PTSD treatment to further improve psychotherapy treatment outcomes. For example, identity factors such as ethnicity and gender are still grossly underexamined in relation to PTSD treatment outcomes. Moreover, while a range of effective treatments now exists, little is known about how to optimally match patients to treatments. A recently completed Veterans Affairs 900-participant comparative effectiveness study of PE and CPT may help shed light on this8, as may an in-progress meta-analysis of treatments for patients with co-occurring PTSD and substance use disorder that includes 42 trials and uses individual patient data9. For now, the best practice is to use shared decision making between patient and provider to inform treatment choice. Knowledge that would allow for more personalized or precision recommendations has the potential to be a force multiplier in enhancing outcomes. In summary, we are fortunate to be in a time where over 40 years of research have given us a menu of effective PTSD psychotherapy options from which patients and their providers can choose. While gaps remain, more research is underway, allowing for optimism that we will be able to help more people recover more fully from PTSD in the coming years.