The Limitations of Evidence-Based Treatments for PTSD

Source: Boulder Crest Foundation, used with permission

There is general agreement on six psychotherapy-based treatment techniques for posttraumatic stress disorder (PTSD) as the most effective, evidence-based approaches available. These treatment techniques are trauma-focused cognitive behavioral therapy (TF-CBT) interventions that include:

1. prolonged exposure (PE) therapy
2. cognitive processing therapy (CPT)
3. cognitive therapy for PTSD (CT for PTSD)
4. eye movement desensitization and reprocessing (EMDR)
5. a class of treatments referred to as “combined somatic/cognitive therapies”
6. a less intensive treatment approach termed “self-help with support” (Mavranezouli et al., 2020; Sciarrino, Warnecke, & Teng, 2020; Hamblen et al., 2019).

Medications, primarily selective serotonin reuptake inhibitors (SSRIs), are also evidence-based treatment approaches, though the literature demonstrates clear benefits of psychotherapeutic techniques over the use of medications in treating PTSD (Hamblen et al., 2019). Notably, the U.S. Department of Defense and U.S. Department of Veterans Affairs guidelines no longer endorse these types of medications as first-line treatments for PTSD; instead, they recommend the manualized psychotherapies listed above as primary treatments for PTSD (U.S. Department of Defense and U.S. Department of Veterans Affairs, 2017).

Although there is supporting evidence for the use of each of these techniques with PTSD, controversy surrounds which intervention is most effective and who may benefit most from each type of therapy. A careful review of the American Psychological Association’s (APA) clinical practice guidelines (CPGs), along with current psychological literature, reveals that while there are strong recommendations for clinicians to use these evidence-based techniques to treat PTSD symptoms, a range of less-than-favorable outcomes is possible for people who receive treatment (Mavranezouli et al., 2020; Sciarrino, Warnecke, & Teng, 2020; Hamblen et al., 2019).

This phenomenon, termed “between-trial heterogeneity,” is complex and thought to be related to issues with large percentages of patients dropping out from treatment, not responding to treatment, patients presenting with differing levels of baseline symptom severity, individual case complexity, comorbidity of PTSD with other medical and mental health issues, and more (Mavranezouli et al., 2020; Steenkamp, Litz, & Marmar, 2020). Evidence is also sparse regarding the long-term effectiveness of evidence-based PTSD treatments overall (Mavranezouli et al., 2020).

Evidence-Based Practices for Military, Veteran, and First Responder PTSD

As a whole, the Department of Defense (DoD) and Veterans Affairs (VA) tend to use TF-CBT interventions to address military-related posttraumatic stress disorder. Specifically, prolonged exposure (PE) therapy and cognitive processing therapy (CPT) are the two most commonly used intervention techniques (Steenkamp, Litz, & Marmar, 2020). Research is sparser surrounding the most common psychological treatments used with non-military first responders, and TF-CBT and PE appear to be two common approaches studied and used with this population (Winders et al., 2021; Haugen, Evces, and Weiss, 2012).

Randomized controlled trials (RCTs) directly examining the use of these interventions in military and veteran populations have demonstrated the potential for both techniques to reduce PTSD symptoms (Steenkamp, Litz, Hoge, & Marmar, 2015). However, significant limitations have been noted with these techniques just as they have been noted in studies involving the broader population.

In fact, recent clinical trials investigating TF-CBT techniques alongside non-trauma-focused treatment techniques in military populations demonstrated that neither PE nor CPT was more effective than non-trauma-focused treatment in reducing PTSD symptoms (Steenkamp, Litz, & Marmar, 2020). These results are concerning and necessitate a closer examination of the significant limitations associated with evidence-based techniques. Let’s take a closer look at some mechanisms thought to be responsible for the limited efficacy of existing treatments.

Limitations of Evidence-Based Practices

1. Marginal benefits of leading PTSD treatments over other therapeutic techniques.

A 2015 review of psychotherapy treatments for military-related PTSD demonstrated that PE and CPT were associated with only marginally better results than non-trauma-focused treatments, and the outcomes that these treatments produced in patients were highly variable (Steenkamp et al., 2015).

More recently, in 2020, a review examining clinical trials of psychotherapy treatments for military-related PTSD since 2015 found that leading trauma-focused treatment techniques and non-trauma-focused treatments did not yield significantly different PTSD outcomes (Steenkamp, Litz, & Marmar, 2020). Rather, effects were similar across all active treatments (including PE, CPT, person-centered therapy, medication, and transcendental meditation interventions; Steenkamp, Litz, & Marmar, 2020).

Post-Traumatic Stress Disorder Essential Reads

Can Art Be Data?

Undoing Emotional Numbing May Be Key to Trauma Recovery

When different interventions achieve very similar results like this, it is natural to consider possible commonalities across treatments that may be responsible for similar outcomes. Indeed, researchers have uncovered mechanisms that appear common across these psychotherapeutic techniques, including psychoeducation, imaginal exposure, cognitive processing, cognitive restructuring, and meaning-making (Mavranezouli et al., 2020). Additionally, it appears that all of these effective, evidence-based PTSD treatments comprise structured therapies delivered by certified healthcare professionals (Mavranezouli et al., 2020).

Lastly, research points to the interpersonal relationship between patient and therapist, known as a “therapeutic alliance,” as a powerful predictor of reduction in PTSD symptoms across treatments (Ellis, Simiola, Brown, Courtois, & Cook, 2018). The apparent benefits of current evidence-based treatments for PTSD over non-trauma-focused treatment approaches are marginal if any, likely due at least in part to these commonalities across treatment techniques.

2. High rates of patient nonresponse and dropout from treatment.

In addition to leading treatments having marginal benefits over other treatments, treatment nonresponse and treatment dropout are major hurdles for current evidence-based treatments (Schottenbauer, Glass, Arnkoff, Tendick, & Gray, 2008; Steenkamp et al., 2015). It is not uncommon for treatment nonresponse rates to be as high as 50 percent on some measures of expected outcome responses to treatment (Scottenbauer et al., 2008). This represents an extremely high percentage of individuals not responding to or reporting zero benefit from treatment.

Further, the rate of patient dropout from PE and CPT treatments consistently falls between 24 and 39 percent (Steenkamp, Litz, & Marmar, 2020). These numbers are concerning as the DoD and VA continue to invest in evidence-based interventions that fail to produce results in large percentages of military and veteran populations.

Treatment Nonresponse

Treatment nonresponse is generally taken to mean that the intervention is not successful for particular patients. While it is concerning that nonresponse rates are so high, even more concerning is that nonresponse rates have been left out of presentations of evidence-based therapy techniques.

According to a comprehensive review of treatment nonresponse and dropout in PTSD patients, deficits exist with how nonresponse is measured, recorded, and reported across studies (Scottenbauer et al., 2008). Reporting pre- and post-treatment averages on specific outcome measures for groups of patients is the norm—a technique that allows data presentation to highlight significant improvements for certain groups while concealing details of individuals who did not benefit from treatment (Scottenbauer et al., 2008).

Additionally, criteria for defining “response to treatment” remain unclear, leaving room for researchers to highlight “good end-state functioning” based on individualized study methods (Scottenbauer et al., 2008). Inconsistencies like these make it difficult to assess the effects of treatments across studies, and a careful examination of the literature highlights a longstanding trend of treatment nonresponse in evidence-based PTSD treatments.

Patient Dropout

In addition to treatment nonresponse, current interventions are subject to consistently high rates of patient dropout, where a patient elects not to finish the course of treatment. Research also reveals that trauma-focused treatments tend to have higher rates of dropout than non-trauma-focused techniques (Edwards‐Stewart et al., 2021).

It is relevant to consider patient dropout in relation to PE and CPT techniques in particular, as both are forms of exposure therapy, where a patient is encouraged to recount and cognitively process a traumatic experience. Exposure-based therapy techniques are among the most controversial due to the intense emotional investment required by patients in order to directly re-examine details of a traumatic event (Scottenbauer et al., 2008).

Indeed, almost half of patients who drop out are thought to terminate treatment due to distress and/or avoidance (Eftekhari, Crowley, Mackintosh, & Rosen, 2020). There are important questions surrounding how beneficial exposure-based therapy techniques are given the high emotional demand on the patient, especially as alternative non-trauma-focused techniques demonstrate lower rates of dropout and nonresponse while offering similar levels of therapeutic benefits (Steenkamp, Litz, & Marmar, 2020; Edwards‐Stewart et al., 2021).

3. High percentage of patients retain PTSD diagnosis after treatment.

One of the most concerning limitations of current evidence-based practices in treating military-related PTSD is the rate of patients continuing to struggle with symptoms after completing a full course of treatment (Steenkamp, Litz, Hoge, & Marmar, 2015).

Across recent clinical trials, between 60 and 72 percent of patients reported symptoms persisting at levels qualifying them for PTSD, despite some improvement (Steenkamp, Litz, & Marmar, 2020). To be clear, these patients continue to experience the disorder to the extent that it causes clinically significant distress or impairment in important areas of their life (American Psychiatric Association, 2013). Only 31 percent of patients in recent military-related PTSD treatment trials were judged recovered from PTSD (Steenkamp, Litz, & Marmar, 2020).

In a more recent study assessing the residual symptom of hyperarousal following treatment of PTSD in active-duty military personnel, 61 percent of the sample were labeled as “suboptimal responders” following treatment with cognitive processing therapy as compared to 21 percent who were identified as “recovered” and 18 percent who were identified as “improved” (Miles et al., 2022). These low rates of recovery necessitate critical questions about whether emerging treatment techniques should be considered as first-line techniques in treating military, veteran, and first responder populations, over and above current practices.

Concluding Thoughts

As noted above, there are a number of challenges related to the most popular evidence-based therapies for PTSD. Patient engagement and satisfaction with these treatments are problematic as are high dropout rates and less than robust responses to the interventions. In the next article, we discuss an alternative to traditional talk therapies for PTSD.

We would like to thank Taryn Greene, Ph.D. for her work on this review for the Boulder Crest Institute.