Authors’ Note: This project described was supported by Award Number RC1 MH088454 from the National Institute of Mental Health (NIMH). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Mental Health, the National Institutes of Health or the Department of Veterans Affairs. Please address all correspondence to: Joan M. Cook, Ph.D., Yale School of Medicine, 950 Campbell Avenue, National Center for PTSD; NEPEC/182, West Haven, Connecticut, 06516; Email: Joan.Cook@yale.edu.
The U.S. Department of Veterans Affairs (VA) is one of the largest comprehensive health care systems in the world. Although unique in some regards, it can serve as an ideal laboratory to study the implementation of evidence-based treatments (EBTs) given the abundance of federal funding and top-down administrative support. The VA provides an organized, centralized environment, free of some barriers faced in other more fragmented segments of the health care system (e.g., lack of funding; Solberg, 2009). Lessons learned within the VA may help other health care systems overcome challenges associated with the implementation of EBTs.
In 2007, the VA instituted nationwide training initiatives in 16 EBTs for various mental and behavioral health conditions (Karlin & Cross, 2014) including two for posttraumatic stress disorder (PTSD):, Prolonged Exposure (PE; Foa, Hembree, & Rothbaum, 2007) and Cognitive Processing Therapy (CPT; Resick & Schnicke, 1993).
These efforts have been extensive and include multiple day face-to-face trainings, intensive follow-up consultation with nationally recognized experts, and audiotape review of patient sessions by trained specialists (Karlin et al., 2010).
Other top-down initiatives supporting the use of these treatments include a mandated VA policy that all veterans with PTSD have access to PE or CPT (U.S. Department of Veterans Affairs and Department of Defense, 2010), development of a national mentoring program to promote regional and national communication between clinic managers (Bernardy, Hamblen, Friedman, Ruzek, & McFall, 2011), and at least one staff member appointed at each medical center to coordinate and champion the use of EBTs.
Even with these unprecedented dissemination efforts, to date, adoption of PE and CPT appears relatively low depending on the treatment setting (Cook, Dinnen, Thompson, Simiola, & Schnurr, 2014; Finley et al., 2015; Mott et al., 2014; Shiner et al., 2012). For example, in a study of nearly 2,000 veterans receiving mental health treatment at VA outpatient PTSD clinics in the Northeast, only 6.3% of veterans received at least one session of PE or CPT (Shiner et al., 2012). However, in 38 VA residential PTSD treatment programs across the U.S., the use of EBTs was considerably higher (Cook, Dinnen, Thompson et al., 2014).
As part of a federally-funded longitudinal investigation, 38 residential PTSD treatment programs with over 200 providers have been followed to understand the barriers and facilitators to implementation of PE and CPT (Cook, Dinnen, Simiola, Thompson et al., 2014). Of the 38 programs, almost 70% reported implementing CPT as full or partial protocol. Although implementation rates for PE showed a substantial increase over a four-year period, almost one fourth (n = 9) of programs were not using PE with any of their patients, no program had adopted PE as the core of their programming, and one program had discontinued its use.
Higher rates of CPT implementation in VA residential settings may be related to the flexibility within the protocol to deliver the treatment in group or individual formats, and with the option of removing the trauma narrative without a reduction in efficacy (CPT-Cognitive; Resick et al., 2008; Cook, Dinnen, Coyne et al., 2014).
Indeed, the most commonly cited barrier to implementing PE across these programs was insufficient time and dedicated resources (Cook, Dinnen, Simiola, Thompson et al., 2014).
For example, numerous providers indicated they lacked adequate resources (e.g., audio recorders, trained providers), while others felt they did not have the flexibility in their schedule to block 90-minute individual sessions at least weekly if not more. At sites that utilize group programming as their primary or sole method of treatment delivery, providers indicated that the lack of efficacious VA-approved group PE protocol inhibited their ability to offer PE as a group option to veterans. Thus, given the lower adoption rates of PE versus CPT, this paper focuses on overcoming organizational challenges to implementing PE in VA PTSD residential treatment programs.
PE is a manualized trauma-focused EBT delivered on an individual basis, for an average of eight to 15 sessions. The treatment, based on emotional processing theory (Foa & Kozak, 1986), has four primary components: psychoeducation, breathing retaining, in vivo exposure, and imaginal exposure. In vivo exposure involves repeated, systematic confrontation to distress-provoking situations that are safe but otherwise avoided due to trauma-related anxiety. Engagement in these situations advances from moderate to more distress-evoking based on a hierarchy developed by the patient and therapist. During imaginal exposure, patients are asked to revisit and recount traumatic memories out loud in detail.
Randomized controlled trials have demonstrated that exposure therapy for military-related PTSD is superior to no treatment and to supportive or psychodynamic therapies (for review, see Steenkamp & Litz, 2013). In addition, data from over 800 VA providers who completed the VA training initiative and treated nearly 2,000 patients with PE indicated significant reductions in PTSD and depression symptoms among male and female veterans of all war eras and veterans with combat-related and non-combat-related PTSD (Eftekhari et al., 2013).
Residential PTSD programs have been a cornerstone of VA health care for over 40 years (Rosenheck, Fontana, & Errera, 1997) and primarily treat veterans who have severe symptomatology, complex life problems and less community support than outpatients (Walter, Varkovitzky, Owens, Lewis, & Chard, 2014). Ideally, residential settings could provide the opportunity to deliver PE over an extended period of time and to closely monitor any potential symptom exacerbation for patients. These programs offer a secure setting where the veterans are removed from daily external stressors, such as relationship or job stress, which might interfere with EBT engagement and adherence.
Despite this, providers in residential programs noted several challenges to EBT use, particularly PE (Cook, Dinnen, Simiola, Thompson, et al., 2014). Although there are numerous reports in the literature on how to address perceived provider and patient barriers to implementing PE (e.g., Cook, Schnurr & Foa, 2004; Feeny, Hembree, & Zoellner, 2004), there are as yet no reports of how to address organizational or logistical obstacles to the delivery of PE in treatment programs.
Thus, the goal of this article is to illustrate how VA residential PTSD treatment programs that were part of a longitudinal investigation overcame organizational challenges to innovatively implement PE.
Data presented here come from a longitudinal investigation of the implementation of two EBTs, CPT and PE, in 38 VA residential PTSD programs reporting patient outcome monitoring data to the VA’s Northeast Program Evaluation Center (NEPEC). The majority of programs participating in the longitudinal study were residential rehabilitation programs followed by domiciliaries, evaluation and brief treatment PTSD units, specialized inpatient PTSD units, and day hospitals (with lodging available upon request).
In total, 243 VA residential PTSD directors, providers and staff were contacted for follow-up participation in a semi-structured interview following initial baseline contact which occurred one to two years prior to this data collection point. Providers were contacted if they participated in the first wave of data collection or were identified by program directors as providing direct clinical care to veterans within the residential program and/or were eligible for training in EBTs.
In total, 198 participated (81%). Most were psychologists (n = 110, 55.6%), followed by social workers (n = 66, 33.3%), nurses (n = 11, 5.6%), psychiatrists (n = 5, 2.5%) and others (n = 6, 3.0%) such as recreation and addiction specialists.
Information presented here was extracted from the semi-structured interviews of providers within programs offering PE or elements of PE. Interviews were audio recorded with permission and professionally transcribed.
Detailed information on the 29 (76%) programs that implemented PE in whole or parts are reported in Table 1. The illustrations that follow demonstrate how PE was utilized in these programs despite perceived organizational challenges.
Implementation of the Full PE Protocol
Implementation of the full PE protocol took place in a number of ways:
1. PE track
Veterans at one residential PTSD treatment program were selected to participate in a PE-track based on their intake assessment and discussions with referring providers. This 12-bed unit has an average length of stay of 30 days, however veterans participating in this PE track remain in the program for eight weeks. Veterans who are not in the PE track participate in a four week coping skills program. Occasionally, a veteran will begin the PE track directly after completing the coping skills portion, increasing their length of stay to 12 weeks.
In any given treatment cohort, approximately 3-4 of the 12 veterans participate in the PE track. Imaginal exposure takes place on a biweekly basis in 90-minute individual sessions. Patients are required to listen to the audio-recordings of their imaginal sessions in group format with individual MP3 players and headphones. A trained mental health technician is present during this group to assist the veteran with any related distress or technological issues.
As a part of individual treatment, providers also work with veterans to develop in vivo hierarchies. In vivo exercises are completed both within the VA campus on weekdays as well as off campus on weekends. Upon return from weekend pass, veterans participate in an hour-long group to review completed in vivo assignments and associated ratings on subjective levels of distress scale (SUDS; Wolpe, 1969).
2. PE as an option within a trauma processing track
A few programs (n = 4) offer trauma processing tracks in which PE is one of the two treatments (the other being CPT) offered. The structure of these programs has been revised to support the use of PE, including extended length of psychotherapy sessions, opportunities for veterans to complete in vivo exposure assignments (e.g. providing weekend passes for veterans) and availability of technical equipment (e.g. audio recorders and headphones) to allow for veterans to engage in imaginal exposure homework.
In the trauma processing track of these programs, patients are typically given a description of PE or CPT by their primary provider. Often times, providers will show videos on these EBTs that the VA has developed to assist in the implementation efforts. These videos include veterans describing their experiences with the treatments.
According to the providers at these programs, patient preference is taken into account and the patient and provider share decision-making regarding which EBT is chosen. If the treatment choice is PE, it is delivered on an individual basis. Each of these programs run separate schedules for those participating in trauma processing versus other programming tracks. Extended stays and additional time slots are accommodated in the trauma processing track to fit the requirements for the provision of the full protocol.
In one of the programs utilizing trauma track-based programming, CPT is the predominant treatment utilized. However, select patients can participate in PE. In this case, individual PE is offered to patients either after completion of group CPT or if the veteran is perceived as having difficulty completing CPT due to reading or writing limitations
3. Select patients receive PE
The majority of residential programs (n = 15) that offer PE as a full protocol do so to select patients. Typically in these programs, PE is delivered in individual sessions at least twice weekly. In several of these settings, the program discharge date can be extended if patients are unable to complete the full protocol within the allotted length of stay. In other settings, providers may be able to continue to complete the protocol with a veteran post-discharge on an outpatient basis. In vivo assignments are generally completed in the evening or over the weekend on an individual basis.
Some programs created PE support groups for veterans. For example, one program has a regularly scheduled and supervised “study hall” where veterans complete or obtain assistance on their imaginal or in vivo homework assignments. Another program created a group where veterans participating in individual PE could come together to discuss their experiences and receive support from their peers.
4. Patients receive PE from outpatient providers during their residential stay
One program was restructured so patients could receive PE from outpatient providers while staying on the residential unit. In this program, the residential providers make requests for consults with outpatient providers for patients who are deemed appropriate for or request PE. Residential providers consider this service a benefit to the veterans since they report being unable to provide PE due to time and delivery constraints (e.g., length of stay, other therapy and case management responsibilities, and provision of psychotherapy in group format only). This program has nearly 50 veteran-occupied beds at a given time. By working closely with the outpatient providers, the residential program has been able to offer PE to their patients despite limited staffing on the unit and limited VA PE training and certification in their residential providers.
Implementation of Partial PE Protocol
While the reasons for partial use primarily involved perceived structural barriers, such as lack of time and resources, it also reflects programs’ preferences for other psychotherapies (e.g. CPT, supportive therapy) or a belief that elements of PE, such as in vivo exposure, were effective and complementary to other programming provided.
1. In vivo group
Some programs (n = 8) implemented only elements of the PE protocol, namely in vivo exposure. Most of these programs offered groups in which providers assisted patients in systematically creating in vivo hierarchies and approaching situations, people or places that were previously avoided due to trauma. Separately or as a group, veterans participate in in vivo activities within areas of the medical center (e.g., sitting in a crowded waiting room) or in the community (e.g., visiting a war memorial, supermarket or movie theater). Following in vivo assignments, veterans are given time in group to discuss the experience, provide support for one another, and review SUDs levels. One program offers one week of group psychoeducation on in vivo exposures (e.g., explanation of the rationale, teaching and reviewing SUD levels) and the following week on outings to complete actual in vivo assignments.
Despite a growing number of VA providers trained in PE, actual treatment usage appears relatively low in outpatient settings (Shiner et al., 2013). As part of a longitudinal investigation on the use of PE and CPT in VA residential PTSD treatment settings nationwide, use of PE appears somewhat higher (Cook, Dinnen, Thompson et al., 2014).
In some ways, residential settings can be seen as ideal for the delivery of PE as patients are typically in these settings over an extended period of time and the staff has the opportunity to closely monitor any potential symptom exacerbation. However, organizational and structural barriers such as insufficient treatment blocks (e.g., less than 90-minutes for sessions), programmatic structure allowing for only group-based programming, and limited number of staff trained to deliver individual treatment have been identified by VA PTSD providers as limiting their ability to implement PE (Cook, Dinnen, Simiola, Thompson et al., 2014).
Though at the time of data collection no VA PTSD residential treatment program reporting outcome data to NEPEC had adopted PE as the core of their treatment, varying degrees of PE were being used. Sharing the innovative implementation of PE in these programs may assist administrators and leaders to develop creative ways for implementing this under utilized EBT. Indeed, these program descriptions provide evidence that implementation of PE is possible within large health care systems and demonstrate how science can be translated into practice. Some programs have created track programming. Others are offering PE to select patients who they considered best suitable for the treatment.
Though reportedly unable to adhere to the full PE treatment protocol due to organizational barriers, many programs incorporate pieces of the PE protocol such as in vivo in a group format.
One residential program chose to partner with the outpatient clinic to ensure that veterans had access to EBTs that the unit providers were unable to deliver themselves. In all cases, only select veterans received the PE and no program adopted PE as the core of treatment programming.
Overcoming barriers to the implementation of EBTs can be difficult. In addition to organizational challenges, patient and provider level barriers to implementation of PE have also been identified. For example, some providers have concerns regarding whether patients psychiatric comorbidities (e.g., substance misuse, dissociation, self-injurious behaviors, active suicidal ideation) are dissuading factors for its use (Cook, Dinnen, Simiola, Thompson et al., 2014).
Further, patient preference including motivation to engage in treatment (Simiola, Nelson, Thompson, & Cook, 2015) may also impact utilization of PE. Despite real or perceived barriers, providers in this longitudinal study identified several ways to increase engagement, reviewing educational materials such as DVDs and informational brochures, and including dedicated time to complete homework assignments (e.g., study hall). Further, having supportive leadership such as someone who ensures protected time for delivery of EBTs has also been shown to improve implementation of PE in these settings (Cook, Dinnen, Simiola, Bernardy et al., 2014).
While it may not be feasible for all VA residential PTSD treatment programs to implement the full PE protocol with all patients, finding innovative ways to overcome organizational obstacles and implement this EBT may help with its increased delivery. One way to overcome this may be through flexibility within fidelity. Indeed, in a study of provider’s use of EBTs for behavioral management of children and parenting strategies almost 90% of participants indicated that they modified EBTs in order to meet the needs of their patients, which ranged from minor to significant changes to the protocols (Tomas, Zimmer-Gembeck, & Chaffin, 2013).
While evidence is particularly strong for the combination of imaginal and in vivo exposure, some studies have indicated that patients who only receive in vivo exposure still make significant improvement in the reduction of their PTSD symptoms (for review, see Cahill, Rothbaum, Resick, & Follette, 2009). Although the literature discerning the effective components of PE is limited, one study found that when imaginal exposure is augmented with cognitive restructuring it is more effective at sustaining reductions in PTSD symptomotology than when in combination with in vivo exposure (Bryant, Moulds, Gurthie, Dang, & Nixon, 2003). Similar results were found in another investigation comparing imaginal exposure with and without imagery rescripting (Arntz, Tiesema, & Kindt, 2007). Reductions in PTSD severity did not differ between patients who received imaginal exposure and imagery rescripting and those who only received imaginal exposure.
Increasing access to training and consultation may be another way of improving PE implementation rates. Lack of training has been cited as the top reason for not using exposure therapy for PTSD outside the VA setting and many providers identify that they are not comfortable using exposure treatment (Becker, Zayfert, & Anderson, 2004). Indeed, research suggests that therapist’s negative beliefs about exposure therapy can be modified through didactic training (Deacon et al., 2013).
There may be additional resources available that can assist in implementing the full protocol of PE. For example, recently, a smart phone application was developed to support implementation and adherence to PE (Reger et al., 2013). The device has multiple capabilities including appointment scheduling, alarm reminders, instant access to an in vivo hierarchy and assigned in vivo’s and a summary of homework adherence since last session based on usage which can be reviewed with the therapist. Use of a smartphone application may help reduce implementation barriers faced by some programs and providers. Of course, adherence and resources issues are not eliminated by the smart phone apps but may help to diminish them
There are several limitations that should be considered. Reporting bias and demand characteristics may have been introduced as a self-report methodology was employed. Secondly, the program descriptions focus on residential treatment programs and may not be entirely generalizable to VA outpatient or non-VA settings. Nonetheless, this compilation of innovative techniques for overcoming barriers may encourage providers, administrators and leadership from a variety of treatment settings to implement PE within their programs or practices.
Conclusions and Future Directions
The nationwide VA training initiative in 16 EBTs is unparalleled in any other health care system in the U.S. In particular, the PE training endeavor has been substantial, with almost 2,000 providers attending the 4-day PE workshops. Programs presented here demonstrated innovative ways for overcoming challenges related to implementation of the full protocol of PE. Some sites selected patients based on provider or patient preference while others created a specific track for those engaging in PE. Others used technology (i.e. use of MP3 players and headphones) to increase patient engagement in imaginal exposure exercises despite the group setting.
Additional research is needed to determine the efficacy of the innovative strategies reviewed above. For example, future investigations may compare these various deliveries of PE in regards to patient engagement, retention and outcome. For programs that have real or perceived lack of available time or resources, using components of PE may prove as one way to overcome obstacles that prevent the full implementation of PE.
Cite This Article
Simiola, V., Dinnen, S., & Cook, J. M. (2016, May). Prolonged exposure in VA residential PTSD treatment programs: Using innovation to overcome organizational challenges. [Web article]. Retrieved from: http://www.societyforpsychotherapy.org/prolonged-exposure-va-residential-ptsd-treatment-programs
Arntz, A., Tiesema, M., & Kindt, M. (2007). Treatment of PTSD: A comparison of imaginal exposure with and without imagery rescripting. Journal of Behavior Therapy and Experimental Psychiatry, 38, 345-370.
Becker, C. B., Zayfert, C., & Anderson, E. (2004). A survey of psychologists’ attitudes towards and utilization of exposure therapy for PTSD. Behaviour Research and Therapy, 42, 277-292.
Bernardy, N., Hamblen, J. L., Friedman, M. J., Ruzek, J. I., & McFall, M. E. (2011). Implementation of a posttraumatic stress disorder mentoring program to improve treatment services. Psychological Trauma: Theory, Research, Practice, and Policy, 3, 292-299.
Bryant, R. A., Moulds, M. L., Guthrie, R. M., Dang, S. T., & Nixon, R. D. (2003). Imaginal exposure alone and imaginal exposure with cognitive restructuring in treatment of posttraumatic stress disorder. Journal of Consulting and Clinical Psychology, 71, 706-712.
Cahill, S. P., Rothbaum, B. O., Resick, P. A., & Folette, V. (2009). Cognitive–behavioral therapy for adults. In E. B. Foa, T. M. Keane, M. J. Friedman, & J. A. Cohen (2nd Eds.), Effective treatments for PTSD (pp. 139–222). New York: The Guilford Press.
Cook, J. M., Dinnen, S., Coyne, J. C., Thompson, R., Simiola, V., Ruzek, J., & Schnurr, P. P. (2015). Evaluation of an implementation model: A national investigation of VA residential programs. Administration and Policy in Mental Health and Mental Health Services Research, 42, 147-156.
Cook, J. M., Dinnen, S., Simiola, V., Bernardy, N., Rosenheck, R., & Hoff, R. (2014). Residential treatment for posttraumatic stress disorder in the Department of Veterans Affairs: A national perspective on perceived effective ingredients. Traumatology: An International Journal, 20, 43-49.
Cook, J. M., Dinnen, S., Simiola, V., Thompson, R., & Schnurr, P. P. (2014). VA residential provider perceptions of dissuading factors to the use of two evidence-based PTSD treatments. Professional Psychology: Research and Practice, 45, 136-142.
Cook, J. M., Dinnen, S., Thompson, R., Simiola, V., & Schnurr, P. P. (2014). Changes in implementation of two evidence‐based psychotherapies for PTSD in VA residential treatment programs: A national investigation. Journal of Traumatic Stress, 27, 137-143.
Cook, J. M., Schnurr, P. P., & Foa, E. B. (2004). Bridging the gap between posttraumatic stress disorder research and clinical practice: The example of exposure therapy. Psychotherapy, 41, 374-387.
Deacon, B. J., Farrell, N. R., Kemp, J. J., Dixon, L. J., Sy, J. T., Zhang, A. R., & McGrath, P. B. (2013). Assessing therapist reservations about exposure therapy for anxiety disorders: The therapist beliefs about exposure scale. Journal of Anxiety Disorders, 27, 772-780.
Eftekhari, A., Ruzek, J. I., Crowley, J. J., Rosen, C. S., Greenbaum, M. A., & Karlin, B. E. (2013). Effectiveness of national implementation of prolonged exposure therapy in Veterans Affairs care. JAMA Psychiatry, 70, 949-955.
Feeny, N. C., Hembree, E. A., & Zoellner, L. A. (2004). Myths regarding exposure
therapy for PTSD. Cognitive and Behavioral Practice, 10, 85-90.
Finley, E., Garcia, H. A., Ketchum, N. S., McGeary, D. D., McGeary, C. A., Wiltsey Stirman, S., & Peterson, A. L. (2015). Utilization of evidence-based psychotherapies in veterans affair posttraumatic stress disorder outpatient clinics. Psychological Services, 12, 73-82.
Foa, E.B., Hembree, E.A., & Rothbaum, B.O. (2007). Prolonged exposure therapy for PTSD: Emotional processing of traumatic experiences therapist guide. New York: Oxford University Press.
Karlin, B. E., & Cross, G. (2014). From the laboratory to the therapy room: National dissemination and implementation of evidence-based psychotherapies in the US Department of Veterans Affairs Health Care System. American Psychologist, 69, 19-33.
Karlin, B. E., Ruzek, J. I., Chard, K. M., Eftekhari, A., Monson, C. M., Hembree, E. A., … & Foa, E. B. (2010). Dissemination of evidence‐based psychological treatments for posttraumatic stress disorder in the Veterans Health Administration. Journal of Traumatic Stress, 23, 663-673.
Mott, J.M., Mondragon, S., Hundt, N., Beason-Smith, M., Grady, R.H., & Teng, E.J. (2014). Characteristics of veterans who initiate and complete cognitive processing therapy and prolonged exposure for PTSD. Journal of Traumatic Stress, 27, 265-273.
Resick, P.A., & Schnicke, M. (1996). Cognitive processing therapy for rape victims: A treatment manual. Newbury Park: Sage Publications.
Resick, P. A., Galovski, T. E., Uhlmansiek, M. O., Scher, C. D., Clum, G. A., Young-Xu, Y. (2008). A randomized clinical trial to dismantle components of cognitive processing therapy for posttraumatic stress disorder in female victims of interpersonal violence. Journal of Consulting and Clinical Psychology, 76, 243-258.
Rosenheck, R. A., Fontana, A. F., & Errera, P. (1997). Inpatient treatment of war-related PTSD: A twenty-year perspective. Journal of Trauma Stress, 10, 407-413.
Shiner, B., D’Avolio, L. W., Nguyen, T. M., Zayed, M. H., Young-Xu, Y., Desai, R. A., … & Watts, B. V. (2012). Measuring use of evidence based psychotherapy for posttraumatic stress disorder. Administration and Policy in Mental Health, 40, 311-318.
Simiola, V., Neilson, E. C., Thompson, R., & Cook, J. M. (2015). Preferences for trauma treatment: A systematic review of the empirical literature. Psychological Trauma: Theory, Research, Practice, and Policy, 7, 516-524.
Smith, E. R., Porter, K. E., Messina, M. G., Beyer, J. A., Defever, M. E., Foa, E. B., & Rauch, S. (2015). Prolonged exposure for PTSD in a veteran group: A pilot effectiveness study. Journal of Anxiety Disorders, 30, 23-27.
Solberg, L. (2009). Lessons for non-VA care delivery systems from the US department of veterans affairs quality enhancement research initiative: QUERI series. Implementation Science, 4, 9-13.
Steenkamp, M. M, & Litz, B. T. (2013). Psychotherapy for military-related posttraumatic stress disorder: Review of the evidence. Clinical Psychology Review, 33, 45-33.
U.S. Department of Veterans Affairs and Department of Defense. (2010). VA/DoD Clinical Practice Guideline for the Management of Post-Traumatic Stress. Washington, DC.
Walter, K. H., Varkovitzky, R. L., Owens, G. P., Lewis, J., & Chard, K. M. (2014). Cognitive processing therapy for veterans with posttraumatic stress disorder: A comparison between outpatient and residential treatment. Journal of Consulting and Clinical Psychology, 82, 551-561.
Wolpe, J. (1969). The practice of behavior therapy. New York: Pergamon Press.