Effectiveness of currently available psychotherapies for post‐traumatic stress disorder and future directions

Abstract

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 psychotherapies. 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 effective. Meta-analyses generally show large effect sizes for PTSD symptom reduction and high rates of loss of diagnosis or remission for these treatments. 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). There is also evidence that PTSD can be treated effectively with nontrauma-focused psychotherapies, which generally aim to improve specific skills, but effect sizes are generally smaller than for trauma-focused psychotherapies. 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 therapy. 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 and consensus on alliance and rupture (both suffer from too many definitions and methodological translations that seem too removed from the original conceptualization); b) more research on the causal relation of alliance development and rupture repair (more study of how each of these effect overall change); c) more research on patient (personal characteristics, intervention responsiveness) and therapist (personal characteristics, technical interventions) factors (specifically how these variables moderate alliance development and rupture repair). In addition, there is a need for: d) more research on rupture repair processes, and more efforts to develop observer-based measures and to apply mixed method studies to explore what processes (i.e., specific patient and therapist behaviors and interactions) are essential to repair, and e) more experimental research on alliance-focused trainings (protocols designed to develop therapist abilities to negotiate alliance) and their potential effect on psychotherapy process and outcome. These second-generation efforts could significantly address the risk of failure posed by alliance rupture and consequently redress the rates of failure in psychotherapy, including premature termination and poor adherence to treatment protocol.