Anxiety disorders are a chronic and potentially debilitating public health concern, impacting a large portion of the population while also being among the costliest psychiatric disorders when untreated.1 Effective treatments for anxiety disorders exist, with extant literature supporting exposure-based psychotherapies for sustained gains.2 These exposure-based therapies are rooted in translational learning models of fear extinction, which involve repeated graded exposures to feared and/or avoided stimuli until new memories form with attenuated danger associations and the fear response decreases.3 Despite its reclassification in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition,4 posttraumatic stress disorder (PTSD) retains its anxiety disorder roots in terms of etiology, symptomatology, and treatment.5 Research supports exposure-based therapies for PTSD,6 and the modality with the greatest empirical support is prolonged exposure (PE).7,8
PE is a trauma-focused treatment for PTSD with extensive efficacy and flexibility across patient presentations.7 It is widely recommended in clinical practice guidelines9,10 and demonstrates a large effect size (ES) compared to control conditions (ES = 1.08) in the treatment of PTSD after a wide range of traumatic events (eg, sexual assault and combat trauma).11 A recent meta-analysis found that exposure, including PE specifically, is the PTSD treatment with the strongest supporting evidence.8 PE has been widely disseminated within the Veterans Administration and the Department of Defense,12 increasing its accessibility, particularly to veterans, as well as increasing the number of trained providers.
PE is typically conducted weekly within an outpatient setting over the course of approximately 10 sessions.13 Additionally, there are new daily PE models that use a 2-week intensive outpatient framework.14 The treatment protocol includes imaginal exposure during the session to an index traumatic event and in vivo exposure between sessions to real-life stimuli that are avoided and/or endured with distress. During imaginal exposures and in vivo exposures, patients self-report their subjective level of distress using a scale of 0 to 100 (Subjective Units of Distress Scale [SUDS])15 to monitor emotional activation. These exposures are used to help emotionally process the memory of the traumatic event (eg, reduce and/or tolerate distress) and examine trauma-related cognitions with the aim of developing new perspectives that help the patient move forward in life.
Imaginal exposures start on the third session and are used up until the final session. Each imaginal exposure lasts approximately 45 minutes and is audio recorded to be listened to for homework. The patient is instructed to close his or her eyes and to use the present tense when describing all actions, sensations, thoughts, and emotions experienced during the traumatic event. The clinician uses verbal prompts to help the patient activate as many elements of the memory as possible (eg, “what are you thinking and feeling as you start to receive enemy fire?”), especially the elements that are part of the patient's intrusive experiences (eg, flashbacks and nightmares). The clinician solicits the patient's SUDS ratings every five minutes to track emotional engagement and distress.
Although most patients are able to tolerate conventional imaginal exposure and use it effectively, a significant minority of patients do not benefit.16 Conventional imaginal exposure can include several barriers including difficulty with imaginal visualization, subtle cognitive avoidance strategies (eg, distraction and minimization), and limited clinician control.17,18 Unfortunately, barriers that lead to an inability to engage the memory predict negative treatment outcomes.19 One method that may help combat these barriers is virtual reality exposure therapy (VRE). By removing difficulties related to visualization and avoidance, VRE may enable patients to access and engage the memory more effectively.
Virtual Reality Exposure Therapy
Virtual reality (VR), broadly defined, is a computerized environment that allows for end-users to feel as though they are in the environment and can interact with its elements. A sense of presence in the environment is achieved through multisensory immersion and can be effective in eliciting emotional responses. As such, VR is now being used as an avenue of intervention for psychopathology. Extant methods outfit the user in a head-mounted display with binocular screens that contains a movement tracker to follow the user's head movements within the environment, changing the virtual view in real time with head movements. Further immersion is achieved through stereo headphones, delivery of vibrations through a platform, and presentation of olfactory cues through a machine that uses compressed air to selectively diffuse scents in the environment.
The sense of presence evoked by VR helps elicit real-life emotions associated with the pathology in a controlled environment, which can facilitate the processing of fear. VR allows for gradual, repeated, and individualized exposures for each patient. As such, VR has been shown to be an effective delivery method of exposure therapy in fear of flying, fear of spiders, panic disorder, agoraphobia, and social anxiety.20 Additionally, the benefits of VRE extend to the treatment of PTSD, which was first demonstrated with Vietnam war veterans approximately two decades ago21,22 and has since been shown to be an effective treatment modality for both veterans and civilians.23
VRE for PTSD builds upon the theory, methods, and evidence-base of PE.13 Simply put, VRE for PTSD can be described as PE that incorporates VR to facilitate activation, exposure, habituation, extinction, and emotional processing. In VRE, imaginal exposure to the most traumatic memory is conducted with the eyes open within a virtual environment that helps activate the trauma memory. Extant VR environments are designed to be manipulated by the clinician to match the individual patient's memory. For example, within the Virtual Iraq and Afghanistan software package (Bravemind, developed at the University of Southern California24), if the patient's trauma memory includes a convoy hit by an IED explosion about 50 meters ahead during dusk and just outside of a city, there is a menu of options to accommodate those variables.24 The clinician is able see and hear everything the patient sees and hears.
A common misconception of VRE for PTSD is that the VR simulation functions as a substitute of the trauma memory and the clinician's aim is to desensitize the patient to the virtual experience. The aim of VRE for PTSD is to emotionally process the actual memory, using VR as another tool to engage the patient. As in traditional imaginal exposure, the patient verbally recounts the entire traumatic memory from beginning to end repeatedly. The difference in VRE is that, as the patient describes the event, the clinician matches the virtual environment to the patient's descriptions only to the extent that the VR stimuli help the patient remain engaged. Clinicians are encouraged to follow the rule of “less is more.” It is more effective to ask the patient to visualize and describe details of their memory than use stimuli that are available but might not match and would therefore distract from engagement. Similar to imaginal exposure without VR, the clinician helps the patient remain engaged in the memory by probing the patient to describe thoughts, emotions, and stimuli not simulated (ie, ideographic details such as facial expressions) that occurred during the traumatic event.
Since the first published case study,21 VRE for PTSD has demonstrated feasibility and efficacy with a range of populations.23 Clinical gains of VRE have been shown to last for up to 12 months.25 In the largest clinical trial to date, which compared VRE to PE and a waitlist control, VRE was found to be equally effective as PE in reducing PTSD symptom severity at posttreatment.26 Compared to waitlist, VRE had a significant effect on PTSD symptoms severity using a structured clinical interview (ES = −.81) and survey self-report (ES = −1.26).26 Another recent study indicated VRE may be associated with larger decreases in psychophysiological reactivity than conventional PE (Katz et al., unpublished data). However, clinical gains at treatment follow-up may be more robust in conventional PE.26 One hypothesis is that for some, the VR environment does not match the memory enough to activate it.
Clinicians occasionally express concern regarding the tolerability of VR equipment, although research has failed to find evidence that simulator sickness is a limiting VR side effect.27 Clinical observations can inform who will benefit most from using VRE, namely patients who exhibit difficulty in sufficiently activating and sustaining memory or who are very avoidant. VRE can be of further use in cases where in vivo exposure is not feasible. Treatment matching based on patient characteristics could improve treatment efficacy with one study indicating those in early adulthood and with high hyperarousal symptoms achieved greater gains with VRE.28 Additionally, as developers create more VR environments and make them more customizable, the likelihood of successful treatment matching should increase.
When designing the VR experience for an individual patient, the clinician should work collaboratively with the patient. Upon entering the virtual environment, the clinician adjusts the setting to match the patient's described experience including time of day, cloudy or clear skies, populated or deserted, or chatter or silence. Small aspects of the environment can be very activating such as hearing certain music or insects buzzing or a dog barking. Some VRE systems have olfactory stimuli such as the smell of garbage, body decomposition, body odor, and alcohol. These choices are dynamic, and the clinician should make them in real time as the patient describes them. Once the clinician is familiar with the trauma narrative, it facilitates matching; for example, local villagers vacating a marketplace immediately before an explosion.
Mismatches between the memory and the VR simulation are not uncommon, but most are trivial and received by patients as acceptable. However, if a patient has an emotional reaction to a nontrivial mismatch, there is an opportunity for an important discussion during postexposure processing that can facilitate treatment goals. For example, a patient might be bothered that the VR simulation includes an emotionless witness of an accident while the actual witness expressed significant emotion. Exploring why the patient is bothered can help the patient refine their interpretation of the event. Nevertheless, after a nontrivial mismatch is detected, whether emotionally evocative or merely distracting, the clinician must correct the exposure in subsequent exposures.
Consistent with PE, the first two sessions of the protocol emphasize treatment rationale and starting conventional in vivo exposure. Starting on the third session, VRE is used for the entire trauma memory and much attention is given to ensuring the VR simulation is helping the patient activate and sustain the memory. Typically starting in the fifth VRE session, as in PE, the emphasis is on repeated exposure to segments of the memory that are the most emotionally evocative, which are called the “hot spots.” Focusing on hot spots creates a more efficient and precise exposure that can be repeated many times in a single session, thus increasing the likelihood of a reduction and/or tolerance of distress. After the first hot spot no longer elicits intense distress, the clinician will move on to the second most evocative segment and so on. After completing all hot spots, the clinician will guide the patient to narrate the entire memory one last time while immersed in the matching virtual environment.
Although VRE software is designed to be user-friendly and intuitive, using these tools is a clinical competency that benefits from structured training and consultation. Prior to incorporating this tool, clinicians must first have strong competencies in conventional imaginal exposure within the context of PE. When learning these tools, it is essential to have familiarity with each component of the hardware and the maps and functions of each environment. The clinician should practice administering VR imaginal exposures with an associate to gain familiarity with shifting attention between the patient, the simulation, and the clinician controls, all while writing observations to be discussed later with the patient during postexposure processing. Clinicians need to be facile enough using the VR to maintain their focus on the patient.
Although VR environments and equipment are impressive, VRE is only a tool that aids well-delivered, evidence-based treatment. In addition to a potentially cost-prohibitive investment, the current literature does not demand widespread adoption of VRE for PTSD. Further, although the scientific rigor in this area has improved in recent years,17 more work is still needed in understanding how to optimize delivery, select patients, identify the most important sensory cues, and leverage unique mediators (eg, sense of presence).
VRE for PTSD has great promise, especially as cost continues to drop and equipment continues to improve.17 If the past is any indication, the entry cost to VRE will become increasingly accessible, especially as mobile devices such as smartphones and tablets become increasingly capable. Mobile devices also open possibilities for mixed reality environments, allowing for virtual constructions to overlay what a camera sees. In addition to the increased availability of hardware, broadband proliferation and improved internet standards will increasingly allow for the delivery of VRE via the internet. These improvements would also open the possibility of VRE being an important tool in telemedicine. Further, Internet-delivered software can allow for a more accessible software-as-a-service model, allowing clinics to only pay for how much they use the package and mitigating expensive and cumbersome software updates.
Despite potential cost barriers, the current evidence should compel PTSD specialty clinics to consider investing in the equipment and training necessary to make VRE a treatment option. Specifically, VRE seems to be particularly beneficial to patients who are especially avoidant and/or exhibit difficulty in sufficiently activating and sustaining their trauma memories. Clinicians interested in VRE need to monitor the growing empirical literature and accessibility of equipment and education opportunities.
- Greenberg PE, Sisitsky T, Kessler RC, et al. The economic burden of anxiety disorders in the 1990s. J Clin Psychiatry. 1999;60(7):427–435. https://doi.org/10.4088/JCP.v60n0702PMID: doi:10.4088/JCP.v60n0702 [CrossRef]
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- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Arlington, VA: American Psychiatric Publishing; 2013.
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- Watts BV, Schnurr PP, Mayo L, Young-Xu Y, Weeks WB, Friedman MJ. Meta-analysis of the efficacy of treatments for posttraumatic stress disorder. J Clin Psychiatry. 2013;74(6):e541–e550. https://doi.org/10.4088/JCP.12r08225 PMID: doi:10.4088/JCP.12r08225 [CrossRef]
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- American Psychological Association. Clinical practice guideline for the treatment of posttraumatic stress disorder (PTSD) in adults, 2017. https://www.apa.org/ptsd-guideline/ptsd.pdf. Accessed July 16, 2019.
- Department of Veteran Affairs and Department of Defense. VA/DOD clinical practice guideline for the management of posttraumatic stress disorder and acute stress disorder, 2017. https://www.healthquality.va.gov/guidelines/MH/ptsd/VADoDPTSDCPGFinal012418.pdf. Accessed July 16, 2019.
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- Yasinski C, Sherrill AM, Maples-Keller JL, Rauch SA, Rothbaum BO. Intensive outpatient prolonged exposure for PTSD in post-9/11 veterans and service-members: program structure and preliminary outcomes of the Emory Healthcare Veterans Program. http://traumapsychnews.com/2018/01/intensive-outpatient-prolonged-exposure-for-ptsd-in-post-9-11-veterans-and-service-members-program-structure-and-preliminary-outcomes-of-the-emory-healthcare-veterans-program/. Accessed July 23, 2019.
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