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When I think about some of the key therapeutic components that promote recovery for trauma survivors with posttraumatic stress disorder (PTSD), I think about dealing with the memories of the trauma, addressing avoidance of trauma-related reminders that impair their lives, and re-evaluating shifts in thinking about how trauma survivors view themselves, others and the world around them. One of the main reasons I like prolonged exposure (PE) for the treatment of PTSD is that it does such a good job at addressing each of these factors for trauma survivors.

PE is a time-limited, manualized, cognitive-behavioral psychotherapy. In this form of exposure therapy, traumatic memories (i.e., imaginal exposure) and reminders of trauma (i.e., in vivo exposure) are gradually approached to bring about a reduction in trauma-related symptoms, examining information about the trauma and its consequences, and leading to changes in maladaptive trauma-related beliefs about the self, others, and the world.

In the late 1970's, Terence Keane and colleagues first applied exposure therapy to the treatment of trauma-related symptoms in veterans; and in the 1980's, Edna Foa and colleagues recognized the similarities of symptoms of rape survivors with those of veterans and specifically developed prolonged exposure therapy. PE includes components of psychoeducation, breathing retraining, in vivo exposure, imaginal exposure, and processing of the imaginal exposure. Patients are typically seen individually for 9-12 weekly or twice weekly sessions that last 90 to 120 min. See Foa, Hembree, and Rothbaum (2007) for the most recent manual.

Clinically, I routinely work with two groups of clinicians implementing cognitive behavioral therapies, including PE, with trauma survivors. These teams at the University of Washington's Center for Anxiety and Traumatic Stress (UWCATS) and King County Sexual Assault Resource Center (KCSARC) are amazing, thoughtful and caring clinicians ranging from those who are just starting work with trauma survivors to those who have years of real world clinical experience.

The patients they see are the gamut of trauma survivors, including those with histories of childhood sexual abuse, complex comorbidities, ongoing litigation, survivors of human trafficking, torture, rape, veterans, natural disasters, etc. I consistently feel blessed to be working with these men and women who care so much about the lives of their patients and put their hearts and souls into their work. When I was asked to write this column, these are the men and women I asked what I should write about. These are some of the things that they thought you as a reader would most enjoy and find helpful in your own clinical practice applying PE.  

One of our observations over the years is not every trauma survivor "habituates" during imaginal exposure. By habituate, we mean that distress upon recounting the traumatic memory reduces during and between sessions. Although emotional processing theory suggests that this is important for recovery, clinically we often do not see this occurring. Part of the reason for this may simply be a function of the therapy in that as therapists we routinely push for emotional engagement and over time shift to more difficult parts of the trauma memory.

Recently, we looked at data from 116 trauma survivors receiving PE and found that only a minority (35.3 percent) experienced a reliable reduction in distress during revisiting from their first to their last imaginal exposure session (see Bluett, Zoellner, & Feeny, 2014). That means that the majority of our patients did not show a reduction in distress (either in mean level or peak level).

Although those who showed a reduction in distress from the first to the last imaginal exposure session did better across a variety of indices at post-treatment (PTSD, depression, functioning), patients who did not show a reduction also did well at post-treatment, averaging approximately five points higher on PTSD and depression at post-treatment (well within the standard error of the measures) and showing large pre- to post-treatment effects.

We were actually stunned because this calls into one of the main tenants we learned when we started exposure therapy--foster within and between session habituation. Yet, at the same time, this is clinically liberating and fosters us rethinking what factors are driving clinical change. It is liberating in that when we do not see habituation we need not immediately worry as clinicians that our patients are failing to benefit from the therapy.

One thing we rely on is consistently tracking patients PTSD and depression symptoms via self-report every session. This helps us put habituation in context. If symptoms are dropping, we care less about habituation. If both are not changing, then we carefully examine factors impairing therapeutic progress. Nevertheless, when we see habituation, it is clinically good. With those who are not experiencing a reduction in distress over time during recounting trauma memories, one possibility is that these patients are still learning important new information during imaginal exposure such as distress tolerance skills (e.g., I can think about the trauma and although it is hard, I can handle it) and altering the meaning of the trauma (e.g., There was no way I could have escaped).

This is consistent with recent theories about exposure therapy that suggest that persistence with exposure exercises, despite the persistence of fear, may still promote new learning (e.g., Craske et al., 2008). Taking together, many of us think that PE may be teaching or promoting distress tolerance or emotion regulation skills for some patients (e.g., Jerud. Zoellner, Pruitt, & Feeny, 2014), and this is consistent with prevailing theories of extinction learning. Clinically, this argues that we as therapists ask ourselves what is the patient learning by doing exposure and how do we promote new, adaptive learning. The answer need not be distress reduction, per se.    

One place where we believe this new, adaptive learning is likely being consolidated is in the processing of imaginal exposure. This is the time after imaginal exposure (15-20 min) where the patient and the therapist discuss how imaginal exposure went. This part of PE often feels least developed to new therapists, with clinical guidance suggesting open-ended questions and letting the patient rather than the therapist direct the discussion. Little research has examined what constitutes "good" or "bad" processing after imaginal exposure (i.e., understanding processing that promotes symptom reduction).

In PE, not all clinical gains are slow and gradual; rather, some gains are large and fast (Jun, Zoellner, & Feeny, 2012). Often we worry about these rapid changes as to whether or not the constitute real, long-term change; but our data suggests that, for the majority of those who experience sudden gains, they are not reversed and are strongly associated with better treatment outcome. This has made us start looking at factors during the processing section after imaginal exposure that precipitate sudden gains (see Jun, this edition).

Using in-depth coding of PE session content, one of the factors that precedes rapid improvements in symptoms is patient hope. In our work, we often focus more on addressing negative emotions rather than actively promoting positive ones. Yet, in clinical supervision, we often talk having confidence in the therapy (e.g., "This has helped a lot of people just like you."), confidence in the patient (e.g., "You are going to be able to do this."), and pointing to the future (e.g., "Won't it be great, when...").

As a result of this research, we as clinical teams have all been further spurred on in our thinking more about to promote real, not false hope, in our patients. This isn't to say that "hope" is the answer, rather it may be a conduit toward allowing oneself to really emotionally engage with the trauma memory, promoting listening to imaginal exposure tapes, approaching more feared situations outside of the session, rethinking beliefs previously held staunchly, etc. This is simply to say that we as clinicians should not neglect the role of hope in promoting clinical change.

PE has a long, multiple decade history of producing clinically meaningful gains not only in PTSD symptoms but also in improving broader areas of functioning. Yet, treatment development means that exposure therapy for PTSD (or for that matter any psychological treatment) is not a fixed entity but should continue to grow and improve based on emerging data.

I hope (pardon the pun) you will be able to use this new data to enhance your clinical practice applying PE.

About the Author

Lori A. Zoellner, PhD, is a Professor in the Department of Psychology at the University of Washington and Director of the University of Washington Center for Anxiety and Traumatic Stress. Her research and clinical experience focus on the prevention and treatment of PTSD, with particular emphasis on information processing. Email: zoellner@u.washington.edu


Bluett, E. J., Zoellner, L. A., & Feeny, N. C. (2014). Does change in distress matter? Mechanisms of change in prolonged exposure for PTSD. Journal of Behavior Therapy and Experimental Psychiatry, 45, 97-104. doi: 10.1016/j.jbtep.2013.09.003

Craske, M. G., Kircanski, K., Zelikowsky, M., Mystkowski, J., Chowdhury, N., & Baker, A. (2008). Optimizing inhibitory learning during exposure therapy. Behaviour Research and Therapy, 46, 5-27. doi: 10.1016/j.brat.2007.10.003.

Foa, E., Hembree, E., & Rothbaum, B. O. (2007). Prolonged exposure therapy for PTSD: Emotional processing of traumatic experiences therapist guide. Oxford University Press.

Jerud, A. B., Zoellner, L. A., Pruitt, L. D., & Feeny, N. C. (2014). Changes in emotion regulation in adults with and without a history of childhood abuse following posttraumatic stress disorder treatment. Journal of Consulting and Clinical Psychology, 82, 721-730 doi: 10.1037/a0036520

Jun, J., Zoellner, L. A., & Feeny, N. C. (2013). Sudden gains in prolonged exposure and sertraline for chronic PTSD. Depression and Anxiety, 30, 607-613. doi:10.1002/da.22119