Comparing Virtual Reality Exposure Therapyto Present-Centered Therapy with 11 U.S. Vietnam

Veterans with PTSD

David J. Ready, Ph.D.,1,2 Robert J. Gerardi, Ph.D.,1 Andrea G. Backscheider, Ph.D.,3

Nathan Mascaro, Ph.D.,1 and Barbara Olasov Rothbaum, Ph.D.2

Abstract

Eleven Vietnam veterans with war-related posttraumatic stress disorder (PTSD) were randomly assigned to10 sessions of either virtual reality exposure (VRE) therapy within a computer-generated virtual Vietnam en-vironment or present-centered therapy (PCT) that avoided traumatic content and utilized a problem-solvingapproach. Participants were assessed at pretreatment, posttreatment, and 6 months posttreatment by an inde-pendent assessor blind to treatment condition. Nine participants completed treatment with one dropout percondition. No significant differences emerged between treatments, likely due to insufficient power. Althoughcomparison of mean changes in PTSD symptoms for the VRE and PCT conditions yielded a moderate effect size(d¼ 0.56) in favor of VRE at 6 months posttreatment, changes in PTSD scores were more variable, and thereforeless reliable, within the VRE condition. The utility of VRE with older veterans with PTSD is discussed.

Introduction

United States veterans of Vietnam with posttraumaticstress disorder (PTSD) have been found to be less re-

sponsive to interventions than other traumatized popula-tions.1 Most published studies to date have found no lastingchange or have found changes that may not be clinicallysignificant with this patient population.2 There is even evi-dence that some types of PTSD treatment may exacerbate thesymptoms of these veterans,3 and when there is change, therecan also be regression to pretreatment symptom levels onfollow-up assessments.4 The authors have found only fourpublished studies with multiple U.S. Vietnam veterans thatreport statistically and clinically significant reductions inPTSD symptoms 6 months or more after treatment for themajority of patients treated. One of these studies involved theuse of virtual reality (VR) technology to provide individualexposure therapy;5 two used imaginal exposure within grouptherapy,6–7 and one involved individually administeredimaginal exposure.8 The common element of these studies is astrong exposure therapy component. Exposure therapy re-quires the patient to repeatedly confront the memory oftraumatic events by describing these events in a supportiveenvironment. Emotional processing theory9 suggests thatpatients suffer from PTSD because they have developed a

complex fear structure regarding traumatic events and thatthis fear structure must be repeatedly activated in an envi-ronment containing corrective information that leads to ha-bituation and extinction of fear responses. Although therehave been surprisingly few studies of its use with U.S. Viet-nam veterans, exposure therapy is one of the most extensivelystudied treatments for PTSD. The U.S. Department of Veter-ans Affairs recently sponsored a review by Institute of Med-icine (IOM) at the National Academies of Science ofpharmaceutical and psychotherapy treatments for PTSDacross all patient populations.10 The IOM concluded that ex-posure therapies were the only PTSD treatments showingsufficient evidence to conclude effectiveness.

Exposure therapy may be particularly difficult for Vietnamveterans who have been avoiding their war-related memoiresfor decades prior to treatment. Many find it difficult to accessand continue to engage in their traumatic memories longenough to facilitate habituation.11 Advances in computertechnology allow for the creation of computer-generatedenvironments (i.e., VR) that help patients access and stayengaged with their traumatic experiences by providing ex-ternal cues similar to those present in the environment wherethe traumatic events occurred. VR environments combinebody-tracking devices, real-time computer graphics, andaudio to create a highly interactive environment that gives

1Mental Health Service Line, VA Medical Center–Atlanta, Decatur, Georgia.2Emory University School of Medicine, Emory University, Atlanta, Georgia.3Department of Educational Psychology, University of Houston, Houston, Texas.

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patients a sense of being present within a specific place. Thepatient wears a head-mounted display that includes head-phones and stereographic miniature computer screens. Pa-tients are able to ‘‘move’’ around within these environmentsby the manipulation of a joystick or head=body movements.As a result, the sense of presence is quickly established. Tworecent meta-analyses found VR to be an effective treatmentfor phobias.12–13

One of the first uses of VR-based exposure (VRE) therapyfor PTSD was with a Vietnam veteran who had already beenin treatment for several years at a VA Medical Center. He wasexposed to the two virtual Vietnam environments utilized inthe present study (described herein). He had clinically sig-nificant and lasting reductions in both PTSD and depres-sion.11 This was followed by VRE with nine additionalVietnam veterans. Six-month post-VRE assessments foundclinically and statistically significant reductions in PTSDsymptoms of these veterans.5 Using the same protocol, Readyet al. treated an additional five Vietnam veterans with VRE.When the data from these two open trials were combined,statistically and clinically significant reductions were foundin PTSD symptoms at both the immediate posttreatment as-sessment and the 6-month posttreatment assessment.14 Acase report of a Vietnam veteran with significant guilt re-ported a reduction in PTSD symptoms after VRE at theBoston VA.15

VRE has also been found to reduce the PTSD symptoms ofU.S. service personnel exposed to combat in Iraq. Rizzo et al.16

used VRE to treat 14 Iraq veterans still on active duty withPTSD. There were statistically and clinically significant re-ductions on self-report measures of PTSD and depression forthe majority of these service members, with a large effect size.These symptom reductions were maintained at 3-monthposttreatment assessments. Reger and Gahm17 provide a casereport of an active-duty Iraq veteran who had significantPTSD symptom reduction with VRE treatment. Woodet al.18,19 found reductions in PTSD self-reported measuresand in physiological arousal in responses to trauma cues withVRE with active-duty services Iraq veterans who had signif-icant symptoms of PTSD. Gerardi et al.20 provide a casereport of a postservice Iraq veteran who had clinically sig-nificant reductions in PTSD symptoms after VRE. It is alsonoteworthy that clinicians in other countries are exploring theuse of VRE to help their citizens who have developed PTSDas a result of international conflicts.21,22

The present work was an attempt to conduct a controlledstudy of VRE with Vietnam veterans suffering from chronicand severe PTSD. The hypothesis was that VRE would pro-duce significantly greater reductions in the symptoms ofPTSD and comorbid depression than a control condition thatincluded the nonspecific elements of individual psychother-apy and avoided any discussion of traumatic events (present-centered therapy, or PCT). Unfortunately, we found thispatient population was so challenging to recruit that only 11Vietnam veterans were treated. Six were in the VRE condi-tion, and five were in the control condition.

Methods

Participants

The following were inclusion criteria for study participa-tion: male Vietnam veterans currently in treatment within the

Atlanta VA Medical Center’s Mental Health Clinic for at least3 months with combat-related PTSD with (a) a Clinician-Administered PTSD Scale (CAPS)24 score of greater than 60;(b) not taking psychotropic medication or else stable on suchmedication for at least 3 months; (c) 6 months of sobriety ifthere was a substance abuse history; and (d) the support ofhis VA psychiatrist for participation. The following were ex-clusion criteria: (a) history of or current clinical evidence ofmania, schizophrenia, organic mental disorders, or psycho-ses; (b) presence of prominent suicidal ideation; (c) history ofor current significant cardiac problems or other physicallimitations that may contraindicate exposure therapy; (d)primary traumatic war experiences that could not be simu-lated within the two virtual Vietnam environments utilized inthis study.

Study staff recruited participants by making presentationsto mental health staff within the Atlanta VA Medical Center,distributing flyers in the Mental Health Clinic, advertising onMedical Center–wide VA TV, placing advertisements in localfree weekly newspapers, and announcing the study in on-going PTSD groups. This effort generated 96 telephonescreenings. Thirty-four of these declined participation. Manyexpressed a fear that VRE would cause an increase in PTSDsymptoms. Another 25 did not meet study criteria. Face-to-face assessments were scheduled with 37 potential partic-ipants. Of these, 27 potential participants were assessed.Sixteen did not meet study criteria. Six of these did not havesevere enough PTSD, six had active substance abuse, twowere already in treatment with one of the study psycho-therapists, one could not get permission from his VA psy-chiatrist to participate, and one appeared psychotic. Elevenwere accepted into the study. Six were Caucasian and fivewere African American. Six participants were randomizedinto the VRE condition and five into the PCT control group.The mean age of the VRE group was 57 (range¼ 53–61 years,SD¼ 3.02); the mean age of the PCT control group was 58(range¼ 55–62, SD¼ 3.05 years). Two patients did not com-plete treatment. One VRE patient dropped out in the thirdsession and did not report any negative effects of studyparticipation. Another PCT patient had unexpected sched-uling problems that prevented starting treatment. Ninepatients completed study-related treatment, five in the VRcondition and four in the PCT condition. The study wasconducted at the Atlanta VA Medical Center, was approvedby the local Instructional Review Board, and overseen by theAtlanta VA Medical Center’s Research and DevelopmentCommittee. All patients gave written informed consent.

Measures

Structured Clinical Interview for DSM-IV (SCID).23 Thisis a widely used clinical interview that was conducted atbaseline to rule out excluded diagnoses.

Clinician-Administered PTSD Scale (CAPS).24 This is aninterview based on the diagnostic criteria for PTSD found inDSM-IV. Although containing a total of 30 items that assessboth symptoms and associated features of PTSD, total CAPSscores as typically reported in treatment outcome studiescomprise 17 core items assessing the frequency and intensityof the 17 potential symptoms of PTSD. Widely used for over adecade, the CAPS has excellent reliability and excellent con-vergent and discriminant validity.25 For the present study, its

50 READY ET AL.

coefficient alpha based on the 17 PTSD symptom items was0.54, 0.88, and 0.87 at baseline, posttreatment, and follow-uprespectively.

Beck Depression Inventory (BDI).26 This 21-item ques-tionnaire assesses numerous symptoms of depression. Theauthors report excellent split-half reliability (0.93) and corre-lations with clinician ratings of depression ranging between0.62 and 0.66. In the present study, the BDI had coefficientalphas of 0.92, 0.88, and 0.84 at baseline, posttreatment, andfollow-up respectively.

Procedure

Data collection and analysis. Participants were admin-istered the measures or interviews at pretreatment, post-treatment, and six-month follow-up by a licensed clinicalpsychologist with 3 years of experience working with Viet-nam veterans. She remained blind to treatment condition.Differential changes in depressive and PTSD symptomsacross treatment group were assessed using mixed-designanalysis of variance (ANOVA). Because such inferential an-alyses are not likely to produce statistically significant resultswith such a small sample size, effect size (Cohen’s d) forsymptom change in the VRE versus PCT condition wascomputed. Dependent samples t tests were used to determineif there were significant mean changes in PTSD or depressionsymptoms for either group or in both groups combined.Again, because of the small sample size, Fisher’s exact testwas used to determine if there were more treatment re-sponders (i.e., at least a 10-point reduction in CAPS score) inthe VRE versus PCT condition. We did not attempt to carryscores forward as a mechanism for addressing the missingdata issue at follow-up.

Treatments. During VRE treatment, participants areasked to describe one or two of their most traumatic warexperiences while mentally keeping ‘‘one foot in the war andone foot in the therapist’s office’’ so that they could engage thewar trauma–related fear structure without being over-whelmed by it. The therapist had control over everything theparticipant saw and heard while in the VR environment andprovided trauma-related stimuli in a gradual manner. Parti-cipants were asked to give a Subjective Units of Distress Scale(SUDS) rating (0 to 100) every 5 minutes and to scan theirbody to report levels of tension. The combination of thesemeasures and the participant’s body language gave thetherapist information about how the participant was re-sponding to both internal and external trauma-related stimuli.This information was used to determine how to pace thefrequency and intensity of trauma-related stimuli that thetherapist provided during the VRE sessions. If the participantdid not seem engaged enough while describing traumaticevents, the therapist increased the intensity of trauma-relatedstimuli. If the participant seemed to be overresponding, thetherapist reduced the intensity. This was often accomplishedby increasing or lowering the volume of gunfire or explosions,which had the effect of making these seem closer or fartheraway from the participant. As participants described trau-matic events, the therapist turned on and off trauma-related stimuli in sequence with the participants’ descriptions.

The VRE environments did not have to include all elementsof a participant’s traumatic experience; they just had to have

enough elements to simulate the ‘‘fear structure’’ of his wartrauma experiences. The intensity and frequency of therapist-provided trauma-related stimuli increased as the participantadapted and habituated to his traumatic experiences. If suc-cessful, participant responses to trauma-related stimuli weregreatly diminished both within and outside of the VR envi-ronment. Audiocassette recordings were made of VRE ses-sions, and participants were instructed to listen to them dailybetween sessions in order to provide additional exposure.

Two virtual Vietnam environments were used. Each patientwas exposed to the environment that mose closely resembledhis war-related traumatic experiences. One environment was a‘‘landing zone’’ with rolling hills that included a swampy rice-paddy area surrounded by jungle that was experienced to beabout two acres wide. Participants were given a joystick withwhich they could move around at will within this environ-ment. The visual stimuli the therapist controlled includedmuzzle flashes from the jungle, a bright flash with the sound ofa land mine exploding, helicopters flying overhead, helicopterslanding and taking off, helicopter blades starting and stoppingto rotate, darkness, and fog. The audio effects included junglesounds such as crickets, distant gunfire and explosions, enemymachine gun fire, helicopters, mortars being launched andlanding, rocket explosions, land mines going off, sloshingsounds in the swampy area, screaming, and male voices yell-ing ‘‘Move out! Move out!’’

The other environment resembled a ride on a Huey heli-copter that included different Vietnam-like terrains andtouching down in a ‘‘hot’’ landing zone. Visual effects for thisenvironment included taking off, flying over rice paddies,flying low over a river, flying near mountains, flying overthick jungle, flying up into clouds, and landing in a landingzone similar to the one described above. Available audioeffects included outgoing machine gun fire, radio chatter,incoming gunfire, explosions and yelling upon landing.

PCT was originally developed as a control condition thatincluded the active nonspecific effects of individual psycho-therapy and did not include the active ingredients of cogni-tive behavior therapy.27 PCT is a supportive therapy thatincludes psychoeducation about PTSD, teaching problem-solving techniques, and helping participants through a focuson problems occurring in their lives in the ‘‘here and now.’’During PCT, discussions of traumatic events are avoided infavor of focusing on how to better cope with symptoms re-sulting from war-related traumas with the input of the ther-apist. PCT includes many of the elements of client-centeredpsychotherapy, such as empathy and genuine unconditionalpositive regard.28 Both treatments were delivered in ten90-minute individual psychotherapy sessions.

Results

Of the five veterans in PCT, four completed the measuresat posttreatment and four completed the measures at follow-up. Of the six veterans in the VRE condition, five completedthe measures at posttreatment and four completed the mea-sures at follow-up.

Descriptive statistics for the two scales (CAPS and BDI) arepresented in Table 1, which indicates that although there mayhave been improvement in symptoms for both conditions,there was also tremendous variability in CAPS scores, par-ticularly in the VRE condition at posttreatment and six-month

COMPARING VRE TO PCT WITH VIETNAM VETERANS WITH PTSD 51

follow-up. To examine differential symptom change as afunction of treatment condition, two mixed-design ANOVAswere conducted, one on the CAPS and the other on the BDI.For both analyses, time (pretreatment, posttreatment, follow-up) was the within-participants variable, and treatmentcondition was the between-participants variable. However,there was no statistically significant interaction between timeand treatment condition for CAPS scores, F(2,5)¼ 0.346,p> 0.05, or for BDI scores, F (2,4)¼ 0.535, p> 0.05. As lack ofstatistical significance for this analysis was expected due tosmall sample size, we computed effect sizes for the meanchange in CAPS=BDI scores for VRE versus PCT. A Cohen’s dwas computed based on the difference in mean changes be-tween VRE and PCT divided by the pooled standard devia-tion of those mean changes. The five VRE treatmentcompleters experienced a mean CAPS improvement of 31.8(SD¼ 39.1) from pretreatment to posttreatment and of 25.0(SD¼ 28.1) from pretreatment to follow-up, whereas the fourPCT completers experienced a mean CAPS improvement of23.0 (SD¼ 21.9) from pretreatment to posttreatment and of13.0 (SD¼ 11.3) from pretreatment to follow-up. Such chan-ges yield Cohen’s d effect sizes of 0.28 and 0.56 for the VREcondition at posttreatment and follow-up respectively. As forthe BDI, the five VRE treatment completers experienced amean improvement of 5.0 (SD¼ 8.7) from pretreatment toposttreatment and of 2.3 (SD¼ 7.8) from pretreatment tofollow-up, while the four PCT treatment completers expe-rienced a mean improvement of 5.0 (SD¼ 7.5) from pre-treatment to posttreatment and of 4.3 (SD¼ 8.8) frompretreatment to follow-up. Such changes yield Cohen’s deffect sizes of 0.0 and �0.24 for the VRE condition at post-treatment and follow-up respectively. Table 2 displays themean total CAPS score for each participant at baseline,posttreatment, and follow-up.

We utilized dependent samples t tests to compare changesin each treatment from baseline to posttreatment and baselineto follow-up. Combining groups, there was significant meanimprovement in CAPS scores from pretreatment to post-treatment (t¼ 2.70, p< 0.05) and from pretreatment to6-month follow-up (t¼ 2.58, p< 0.05) but not in BDI scores(t¼ 1.95 and 1.17 for pretreatment to posttreatment and from

pretreatment to follow-up respectively, p> 0.05). However,there was not statistically significant improvement in CAPSor BDI scores when individual treatment conditions wereisolated, with pretreatment to posttreatment and pretreat-ment to follow-up t¼ 1.82 and 1.78 ( p> 0.05) for VRE on theCAPS and t¼ 1.29 and 0.52 ( p> 0.05) on the BDI. For PCT,pretreatment to posttreatment and pretreatment to follow-upt¼ 2.10 and 2.29 ( p> 0.05) on the CAPS and t¼ 1.33 and 0.97( p> 0.05) on the BDI. Table 3 displays the BDI scores for eachparticipant on each of the three assessments.

Discussion

The primary goal of this study was to examine the efficacyof VRE when compared to a control condition that includedthe nonspecific aspects of individual psychotherapy whileavoiding the essential elements of exposure therapy. Thisstudy included randomizations to treatment condition andblind assessment. Unfortunately, the sample size was toosmall for statistically significant differences to emerge be-tween treatments. The difficulty recruiting enough Vietnamveterans to make an adequate test of VRE demonstrates thatthere is so much resistance to VRE on the part of both this

Table 1. Descriptive Statistics

Time of testing

Baseline Posttreatment Follow-up

Treatment (Min, Max) Mean (SD) (Min, Max) Mean (SD) (Min, Max) Mean (SD)

CAPS Total PCT (86, 111) 101.00 (9.51) (45, 98) 75.50 (22.22) (80, 96) 87.00 (6.32)VRE (64, 107) 87.83 (15.43) (6, 86) 59.20 (32.24) (33, 113) 64.75 (34.08)

CAPS Reexperiencing PCT (18, 37) 27.60 (7.30) (7, 30) 18.50 (10.41) (15, 33) 21.80 (6.72)VRE (7, 34) 18.83 (10.25) (0, 29) 16.80 (10.85) (0, 32) 14.50 (13.80)

CAPS Avoidance PCT (34, 37) 35.20 (1.64) (21, 32) 25.00 (4.83) (26, 37) 32.00 (4.18)VRE (25, 42) 32.50 (7.04) (6, 32) 22.20 (10.31) (10, 39) 22.25 (14.17)

CAPS Hyperarousal PCT (30, 34) 32.40 (1.52) (17, 35) 28.50 (7.94) (24, 32) 27.60 (2.97)VRE (20, 37) 29.67 (6.02) (0, 28) 16.80 (10.26) (15, 35) 23.50 (8.50)

BDI PCT (22, 42) 30.00 (7.78) (21, 32) 27.00 (4.97) (18, 35) 25.20 (6.50)VRE (8, 29) 20.33 (7.26) (3, 26) 14.20 (8.23) (13, 18) 15.67 (2.52)

PCT condition: N¼ 5, 4, and 5 at baseline, posttreatment, and follow-up respectively.VRE condition: N¼ 6, 5, and 4 at baseline, posttreatment, and follow-up respectively.BDI, Beck Depression Inventory; PTC, present-centered therapy; VRE, virtual reality exposure.

Table 2. CAPS Scores for VRE and PCT at Baseline,

Posttreatment, and Follow-up

GroupBaselineCAPS

PosttreatmentCAPS

6-Monthfollow-up CAPS

VR 107 35 54VR 64 65 27VR 100 86 113VR 93 — —VR 82 6 59VR 81 83 —PCT 86 77 88PCT 100 45 76PCT 107 98 96PCT 101 82 82PCT 111 — —

PTC, present-centered therapy; VRE, virtual reality exposure.

52 READY ET AL.

patient population and VA mental health clinicians that anadequate test of VRE efficacy with these veterans is difficultto generate. Although study staff attempted to educate bothpotential participants and VA staff about the value of VREcompared to its minimal risk, this had little effect on re-cruitment. It seems the difficulty in getting Vietnam veteransto try VRE may be related in part to this generation notgrowing up with computers, lacking familiarity with theconcept of a computer-generated environment, and beingapprehensive about new technology. This study’s recruit-ment difficulties are consistent with the two earlier AtlantaVA VRE open trials and a VRE study with Vietnam veteransat the Boston VA.15 While it is generally difficult to recruitPTSD participants, whether civilian or military, for exposure-based treatments, as avoidance characterizes the disorder,U.S. Vietnam veterans seem to be even more difficult to re-cruit for VRE treatment. On a positive note, there is evidencethat most active-duty service members, such as those re-turning from Iraq and Afghanistan, would be willing to tryVRE treatment if they developed PTSD.16

Taken as a whole, this study provides some support for thepossible value of VRE while pointing out that the primarydifficulty with further investigation of this treatment modelwith older veterans is participant recruitment. The authorssuggest that future studies of VRE with older veterans focuson developing better ways to recruit and retain participants.

Acknowledgments

This study was funded by Department of Veterans AffairsRehabilitation Research and Development Service GrantD3188P. The authors acknowledge the invaluable contribu-tions of Susan Berel, Amanda Lorenz, and Rebecca Ready tothis project. The Mental Health Service Line of the Atlanta VAMedical Center supported this work, and the AtlantaDepartment of Veterans Affairs Health Services Research &Development Service provided statistical consultation andanalysis.

Disclosure Statement

Dr. Rothbaum is a consultant to and owns equity in Vir-tually Better, Inc., which is developing products related to the

virtual reality research described in this work. The termsof this arrangement have been reviewed and approved byEmory University in accordance with its conflict-of-interestpolicies.

No competing financial interests exist for the other authors.

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Table 3. BDI Scores for VRE and PCT at Baseline,

Posttreatment, and Follow-up

GroupBaseline

BDIPost-treatment

BDI6-Month

follow-up BDI

VR 27 13 16VR 8 13 12VR 25 26 —VR 21 — —VR 17 3 17VR 19 16 —PCT 33 32 35PCT 42 28 26PCT 27 19 21PCT 22 25 25PCT 26 — —

BDI, Beck Depression Inventory; PTC, present-centered therapy;VRE, virtual reality exposure.

COMPARING VRE TO PCT WITH VIETNAM VETERANS WITH PTSD 53

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Address correspondence to:Dr. David J. Ready

Mental Heath Service Line (116A)VA Medical Center–Atlanta

1670 Clairmont RoadDecatur, GA 30033

E-mail: David.Ready@va.gov

54 READY ET AL.