Comparing Virtual Reality Exposure Therapy to Present-Centered Therapy with 11 U.S. Vietnam Veterans with PTSD

Abstract

Eleven Vietnam veterans with war-related posttraumatic stress disorder (PTSD) were randomly assigned to 10 sessions of either virtual reality exposure (VRE) therapy within a computer-generated virtual Vietnam environment or present-centered therapy (PCT) that avoided traumatic content and utilized a problem-solving approach. Participants were assessed at pretreatment, posttreatment, and 6 months posttreatment by an independent assessor blind to treatment condition. Nine participants completed treatment with one dropout per condition. No significant differences emerged between treatments, likely due to insufficient power. Although comparison of mean changes in PTSD symptoms for the VRE and PCT conditions yielded a moderate effect size (d = 0.56) in favor of VRE at 6 months posttreatment, changes in PTSD scores were more variable, and therefore less reliable, within the VRE condition. The utility of VRE with older veterans with PTSD is discussed.

Introduction

United States veterans of Vietnam with posttraumatic stress disorder (PTSD) have been found to be less responsive to interventions than other traumatized populations.¹ Most published studies to date have found no lasting change or have found changes that may not be clinically significant with this patient population.² There is even evidence that some types of PTSD treatment may exacerbate the symptoms of these veterans,³ and when there is change, there can also be regression to pretreatment symptom levels on follow-up assessments.⁴ The authors have found only four published studies with multiple U.S. Vietnam veterans that report statistically and clinically significant reductions in PTSD symptoms 6 months or more after treatment for the majority of patients treated. One of these studies involved the use of virtual reality (VR) technology to provide individual exposure therapy;⁵ two used imaginal exposure within group therapy,^6–7 and one involved individually administered imaginal exposure.⁸ The common element of these studies is a strong exposure therapy component. Exposure therapy requires the patient to repeatedly confront the memory of traumatic events by describing these events in a supportive environment. Emotional processing theory⁹ suggests that patients suffer from PTSD because they have developed a complex fear structure regarding traumatic events and that this fear structure must be repeatedly activated in an environment containing corrective information that leads to habituation and extinction of fear responses. Although there have been surprisingly few studies of its use with U.S. Vietnam veterans, exposure therapy is one of the most extensively studied treatments for PTSD. The U.S. Department of Veterans Affairs recently sponsored a review by Institute of Medicine (IOM) at the National Academies of Science of pharmaceutical and psychotherapy treatments for PTSD across all patient populations.¹⁰ The IOM concluded that exposure therapies were the only PTSD treatments showing sufficient evidence to conclude effectiveness.

Exposure therapy may be particularly difficult for Vietnam veterans who have been avoiding their war-related memoires for decades prior to treatment. Many find it difficult to access and continue to engage in their traumatic memories long enough to facilitate habituation.¹¹ Advances in computer technology allow for the creation of computer-generated environments (i.e., VR) that help patients access and stay engaged with their traumatic experiences by providing external cues similar to those present in the environment where the traumatic events occurred. VR environments combine body-tracking devices, real-time computer graphics, and audio to create a highly interactive environment that gives patients a sense of being present within a specific place. The patient wears a head-mounted display that includes headphones and stereographic miniature computer screens. Patients are able to “move” around within these environments by the manipulation of a joystick or head/body movements. As a result, the sense of presence is quickly established. Two recent meta-analyses found VR to be an effective treatment for phobias.^12–13

One of the first uses of VR-based exposure (VRE) therapy for PTSD was with a Vietnam veteran who had already been in treatment for several years at a VA Medical Center. He was exposed to the two virtual Vietnam environments utilized in the present study (described herein). He had clinically significant and lasting reductions in both PTSD and depression.¹¹ This was followed by VRE with nine additional Vietnam veterans. Six-month post-VRE assessments found clinically and statistically significant reductions in PTSD symptoms of these veterans.⁵ Using the same protocol, Ready et 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 found in PTSD symptoms at both the immediate posttreatment assessment and the 6-month posttreatment assessment.¹⁴ A case report of a Vietnam veteran with significant guilt reported a reduction in PTSD symptoms after VRE at the Boston VA.¹⁵

VRE has also been found to reduce the PTSD symptoms of U.S. service personnel exposed to combat in Iraq. Rizzo et al.¹⁶ used VRE to treat 14 Iraq veterans still on active duty with PTSD. There were statistically and clinically significant reductions on self-report measures of PTSD and depression for the majority of these service members, with a large effect size. These symptom reductions were maintained at 3-month posttreatment assessments. Reger and Gahm¹⁷ provide a case report of an active-duty Iraq veteran who had significant PTSD symptom reduction with VRE treatment. Wood et al.^18,19 found reductions in PTSD self-reported measures and in physiological arousal in responses to trauma cues with VRE with active-duty services Iraq veterans who had significant symptoms of PTSD. Gerardi et al.²⁰ provide a case report of a postservice Iraq veteran who had clinically significant reductions in PTSD symptoms after VRE. It is also noteworthy that clinicians in other countries are exploring the use of VRE to help their citizens who have developed PTSD as a result of international conflicts.^21,22

The present work was an attempt to conduct a controlled study of VRE with Vietnam veterans suffering from chronic and severe PTSD. The hypothesis was that VRE would produce significantly greater reductions in the symptoms of PTSD and comorbid depression than a control condition that included the nonspecific elements of individual psychotherapy and avoided any discussion of traumatic events (present-centered therapy, or PCT). Unfortunately, we found this patient population was so challenging to recruit that only 11 Vietnam veterans were treated. Six were in the VRE condition, and five were in the control condition.

Methods

Participants

The following were inclusion criteria for study participation: male Vietnam veterans currently in treatment within the Atlanta VA Medical Center's Mental Health Clinic for at least 3 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 such medication for at least 3 months; (c) 6 months of sobriety if there was a substance abuse history; and (d) the support of his VA psychiatrist for participation. The following were exclusion criteria: (a) history of or current clinical evidence of mania, schizophrenia, organic mental disorders, or psychoses; (b) presence of prominent suicidal ideation; (c) history of or current significant cardiac problems or other physical limitations that may contraindicate exposure therapy; (d) primary traumatic war experiences that could not be simulated within the two virtual Vietnam environments utilized in this study.

Study staff recruited participants by making presentations to mental health staff within the Atlanta VA Medical Center, distributing flyers in the Mental Health Clinic, advertising on Medical Center–wide VA TV, placing advertisements in local free weekly newspapers, and announcing the study in ongoing PTSD groups. This effort generated 96 telephone screenings. Thirty-four of these declined participation. Many expressed a fear that VRE would cause an increase in PTSD symptoms. Another 25 did not meet study criteria. Face-to-face assessments were scheduled with 37 potential participants. Of these, 27 potential participants were assessed. Sixteen did not meet study criteria. Six of these did not have severe enough PTSD, six had active substance abuse, two were already in treatment with one of the study psychotherapists, one could not get permission from his VA psychiatrist to participate, and one appeared psychotic. Eleven were accepted into the study. Six were Caucasian and five were African American. Six participants were randomized into the VRE condition and five into the PCT control group. The mean age of the VRE group was 57 (range = 53–61 years, SD = 3.02); the mean age of the PCT control group was 58 (range = 55–62, SD = 3.05 years). Two patients did not complete treatment. One VRE patient dropped out in the third session and did not report any negative effects of study participation. Another PCT patient had unexpected scheduling problems that prevented starting treatment. Nine patients completed study-related treatment, five in the VR condition and four in the PCT condition. The study was conducted at the Atlanta VA Medical Center, was approved by the local Instructional Review Board, and overseen by the Atlanta VA Medical Center's Research and Development Committee. All patients gave written informed consent.

Measures

Structured Clinical Interview for DSM-IV (SCID)²³

This is a widely used clinical interview that was conducted at baseline to rule out excluded diagnoses.

Clinician-Administered PTSD Scale (CAPS)²⁴

This is an interview based on the diagnostic criteria for PTSD found in DSM-IV. Although containing a total of 30 items that assess both symptoms and associated features of PTSD, total CAPS scores as typically reported in treatment outcome studies comprise 17 core items assessing the frequency and intensity of the 17 potential symptoms of PTSD. Widely used for over a decade, the CAPS has excellent reliability and excellent convergent and discriminant validity.²⁵ For the present study, its coefficient alpha based on the 17 PTSD symptom items was 0.54, 0.88, and 0.87 at baseline, posttreatment, and follow-up respectively.

Beck Depression Inventory (BDI)²⁶

This 21-item questionnaire assesses numerous symptoms of depression. The authors report excellent split-half reliability (0.93) and correlations with clinician ratings of depression ranging between 0.62 and 0.66. In the present study, the BDI had coefficient alphas of 0.92, 0.88, and 0.84 at baseline, posttreatment, and follow-up respectively.

Procedure

Data collection and analysis

Participants were administered the measures or interviews at pretreatment, posttreatment, and six-month follow-up by a licensed clinical psychologist with 3 years of experience working with Vietnam veterans. She remained blind to treatment condition. Differential changes in depressive and PTSD symptoms across treatment group were assessed using mixed-design analysis of variance (ANOVA). Because such inferential analyses are not likely to produce statistically significant results with such a small sample size, effect size (Cohen's d) for symptom change in the VRE versus PCT condition was computed. Dependent samples t tests were used to determine if there were significant mean changes in PTSD or depression symptoms for either group or in both groups combined. Again, because of the small sample size, Fisher's exact test was used to determine if there were more treatment responders (i.e., at least a 10-point reduction in CAPS score) in the VRE versus PCT condition. We did not attempt to carry scores forward as a mechanism for addressing the missing data issue at follow-up.

Treatments

During VRE treatment, participants are asked to describe one or two of their most traumatic war experiences while mentally keeping “one foot in the war and one foot in the therapist's office” so that they could engage the war trauma–related fear structure without being overwhelmed by it. The therapist had control over everything the participant saw and heard while in the VR environment and provided trauma-related stimuli in a gradual manner. Participants were asked to give a Subjective Units of Distress Scale (SUDS) rating (0 to 100) every 5 minutes and to scan their body to report levels of tension. The combination of these measures and the participant's body language gave the therapist information about how the participant was responding to both internal and external trauma-related stimuli. This information was used to determine how to pace the frequency and intensity of trauma-related stimuli that the therapist provided during the VRE sessions. If the participant did not seem engaged enough while describing traumatic events, the therapist increased the intensity of trauma-related stimuli. If the participant seemed to be overresponding, the therapist reduced the intensity. This was often accomplished by increasing or lowering the volume of gunfire or explosions, which had the effect of making these seem closer or farther away from the participant. As participants described traumatic 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 elements of a participant's traumatic experience; they just had to have enough elements to simulate the “fear structure” of his war trauma experiences. The intensity and frequency of therapist-provided trauma-related stimuli increased as the participant adapted and habituated to his traumatic experiences. If successful, participant responses to trauma-related stimuli were greatly diminished both within and outside of the VR environment. Audiocassette recordings were made of VRE sessions, and participants were instructed to listen to them daily between sessions in order to provide additional exposure.

Two virtual Vietnam environments were used. Each patient was exposed to the environment that mose closely resembled his 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 be about two acres wide. Participants were given a joystick with which they could move around at will within this environment. The visual stimuli the therapist controlled included muzzle flashes from the jungle, a bright flash with the sound of a land mine exploding, helicopters flying overhead, helicopters landing and taking off, helicopter blades starting and stopping to rotate, darkness, and fog. The audio effects included jungle sounds such as crickets, distant gunfire and explosions, enemy machine gun fire, helicopters, mortars being launched and landing, rocket explosions, land mines going off, sloshing sounds in the swampy area, screaming, and male voices yelling “Move out! Move out!”

The other environment resembled a ride on a Huey helicopter that included different Vietnam-like terrains and touching down in a “hot” landing zone. Visual effects for this environment included taking off, flying over rice paddies, flying low over a river, flying near mountains, flying over thick jungle, flying up into clouds, and landing in a landing zone similar to the one described above. Available audio effects included outgoing machine gun fire, radio chatter, incoming gunfire, explosions and yelling upon landing.

PCT was originally developed as a control condition that included the active nonspecific effects of individual psychotherapy and did not include the active ingredients of cognitive behavior therapy.²⁷ PCT is a supportive therapy that includes psychoeducation about PTSD, teaching problem-solving techniques, and helping participants through a focus on problems occurring in their lives in the “here and now.” During PCT, discussions of traumatic events are avoided in favor of focusing on how to better cope with symptoms resulting from war-related traumas with the input of the therapist. PCT includes many of the elements of client-centered psychotherapy, such as empathy and genuine unconditional positive regard.²⁸ Both treatments were delivered in ten 90-minute individual psychotherapy sessions.

Results

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

Descriptive statistics for the two scales (CAPS and BDI) are presented in Table 1, which indicates that although there may have been improvement in symptoms for both conditions, there was also tremendous variability in CAPS scores, particularly in the VRE condition at posttreatment and six-month follow-up. To examine differential symptom change as a function of treatment condition, two mixed-design ANOVAs were 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 treatment condition was the between-participants variable. However, there was no statistically significant interaction between time and treatment condition for CAPS scores, F(2,5) = 0.346, p > 0.05, or for BDI scores, F (2,4) = 0.535, p > 0.05. As lack of statistical significance for this analysis was expected due to small sample size, we computed effect sizes for the mean change in CAPS/BDI scores for VRE versus PCT. A Cohen's d was computed based on the difference in mean changes between VRE and PCT divided by the pooled standard deviation of those mean changes. The five VRE treatment completers experienced a mean CAPS improvement of 31.8 (SD = 39.1) from pretreatment to posttreatment and of 25.0 (SD = 28.1) from pretreatment to follow-up, whereas the four PCT completers experienced a mean CAPS improvement of 23.0 (SD = 21.9) from pretreatment to posttreatment and of 13.0 (SD = 11.3) from pretreatment to follow-up. Such changes yield Cohen's d effect sizes of 0.28 and 0.56 for the VRE condition at posttreatment and follow-up respectively. As for the BDI, the five VRE treatment completers experienced a mean improvement of 5.0 (SD = 8.7) from pretreatment to posttreatment and of 2.3 (SD = 7.8) from pretreatment to follow-up, while the four PCT treatment completers experienced a mean improvement of 5.0 (SD = 7.5) from pretreatment to posttreatment and of 4.3 (SD = 8.8) from pretreatment to follow-up. Such changes yield Cohen's d effect sizes of 0.0 and −0.24 for the VRE condition at posttreatment and follow-up respectively. Table 2 displays the mean total CAPS score for each participant at baseline, posttreatment, and follow-up.

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: N = 5, 4, and 5 at baseline, posttreatment, and follow-up respectively.

VRE condition: N = 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

Group	Baseline CAPS	Posttreatment CAPS	6-Month follow-up CAPS
VR	107	35	54
VR	64	65	27
VR	100	86	113
VR	93	—	—
VR	82	6	59
VR	81	83	—
PCT	86	77	88
PCT	100	45	76
PCT	107	98	96
PCT	101	82	82
PCT	111	—	—

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

We utilized dependent samples t tests to compare changes in each treatment from baseline to posttreatment and baseline to follow-up. Combining groups, there was significant mean improvement in CAPS scores from pretreatment to posttreatment (t = 2.70, p < 0.05) and from pretreatment to 6-month follow-up (t = 2.58, p < 0.05) but not in BDI scores (t = 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 CAPS or BDI scores when individual treatment conditions were isolated, with pretreatment to posttreatment and pretreatment to follow-up t = 1.82 and 1.78 (p > 0.05) for VRE on the CAPS and t = 1.29 and 0.52 (p > 0.05) on the BDI. For PCT, pretreatment to posttreatment and pretreatment to follow-up t = 2.10 and 2.29 (p > 0.05) on the CAPS and t = 1.33 and 0.97 (p > 0.05) on the BDI. Table 3 displays the BDI scores for each participant on each of the three assessments.

Table 3.

BDI Scores for VRE and PCT at Baseline, Posttreatment, and Follow-up

Group	Baseline BDI	Post-treatment BDI	6-Month follow-up BDI
VR	27	13	16
VR	8	13	12
VR	25	26	—
VR	21	—	—
VR	17	3	17
VR	19	16	—
PCT	33	32	35
PCT	42	28	26
PCT	27	19	21
PCT	22	25	25
PCT	26	—	—

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

Discussion

The primary goal of this study was to examine the efficacy of VRE when compared to a control condition that included the nonspecific aspects of individual psychotherapy while avoiding the essential elements of exposure therapy. This study included randomizations to treatment condition and blind assessment. Unfortunately, the sample size was too small for statistically significant differences to emerge between treatments. The difficulty recruiting enough Vietnam veterans to make an adequate test of VRE demonstrates that there is so much resistance to VRE on the part of both this patient population and VA mental health clinicians that an adequate test of VRE efficacy with these veterans is difficult to generate. Although study staff attempted to educate both potential participants and VA staff about the value of VRE compared to its minimal risk, this had little effect on recruitment. It seems the difficulty in getting Vietnam veterans to try VRE may be related in part to this generation not growing up with computers, lacking familiarity with the concept of a computer-generated environment, and being apprehensive about new technology. This study's recruitment difficulties are consistent with the two earlier Atlanta VA VRE open trials and a VRE study with Vietnam veterans at the Boston VA.¹⁵ While it is generally difficult to recruit PTSD 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 recruit for VRE treatment. On a positive note, there is evidence that most active-duty service members, such as those returning from Iraq and Afghanistan, would be willing to try VRE treatment if they developed PTSD.¹⁶

Taken as a whole, this study provides some support for the possible value of VRE while pointing out that the primary difficulty with further investigation of this treatment model with older veterans is participant recruitment. The authors suggest that future studies of VRE with older veterans focus on developing better ways to recruit and retain participants.

Footnotes

Acknowledgments

This study was funded by Department of Veterans Affairs Rehabilitation Research and Development Service Grant D3188P. The authors acknowledge the invaluable contributions of Susan Berel, Amanda Lorenz, and Rebecca Ready to this project. The Mental Health Service Line of the Atlanta VA Medical Center supported this work, and the Atlanta Department of Veterans Affairs Health Services Research & Development Service provided statistical consultation and analysis.

Disclosure Statement

Dr. Rothbaum is a consultant to and owns equity in Virtually Better, Inc., which is developing products related to the virtual reality research described in this work. The terms of this arrangement have been reviewed and approved by Emory University in accordance with its conflict-of-interest policies.

No competing financial interests exist for the other authors.

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Group	Baseline CAPS	Posttreatment CAPS	6-Month follow-up CAPS
VR	107	35	54
VR	64	65	27
VR	100	86	113
VR	93	—	—
VR	82	6	59
VR	81	83	—
PCT	86	77	88
PCT	100	45	76
PCT	107	98	96
PCT	101	82	82
PCT	111	—	—

Group	Baseline BDI	Post-treatment BDI	6-Month follow-up BDI
VR	27	13	16
VR	8	13	12
VR	25	26	—
VR	21	—	—
VR	17	3	17
VR	19	16	—
PCT	33	32	35
PCT	42	28	26
PCT	27	19	21
PCT	22	25	25
PCT	26	—	—

Group	Baseline CAPS	Posttreatment CAPS	6-Month follow-up CAPS
VR	107	35	54
VR	64	65	27
VR	100	86	113
VR	93	—	—
VR	82	6	59
VR	81	83	—
PCT	86	77	88
PCT	100	45	76
PCT	107	98	96
PCT	101	82	82
PCT	111	—	—

Group	Baseline BDI	Post-treatment BDI	6-Month follow-up BDI
VR	27	13	16
VR	8	13	12
VR	25	26	—
VR	21	—	—
VR	17	3	17
VR	19	16	—
PCT	33	32	35
PCT	42	28	26
PCT	27	19	21
PCT	22	25	25
PCT	26	—	—

Comparing Virtual Reality Exposure Therapy to Present-Centered Therapy with 11 U.S. Vietnam Veterans with PTSD

Abstract

Abstract

Introduction

Methods

Participants

Measures

Structured Clinical Interview for DSM-IV (SCID) 23

Clinician-Administered PTSD Scale (CAPS) 24

Beck Depression Inventory (BDI) 26

Procedure

Data collection and analysis

Treatments

Results

Discussion

Footnotes

Acknowledgments

Disclosure Statement

References

Structured Clinical Interview for DSM-IV (SCID)²³

Clinician-Administered PTSD Scale (CAPS)²⁴

Beck Depression Inventory (BDI)²⁶

Group	Baseline CAPS	Posttreatment CAPS	6-Month follow-up CAPS
VR	107	35	54
VR	64	65	27
VR	100	86	113
VR	93	—	—
VR	82	6	59
VR	81	83	—
PCT	86	77	88
PCT	100	45	76
PCT	107	98	96
PCT	101	82	82
PCT	111	—	—

Group	Baseline BDI	Post-treatment BDI	6-Month follow-up BDI
VR	27	13	16
VR	8	13	12
VR	25	26	—
VR	21	—	—
VR	17	3	17
VR	19	16	—
PCT	33	32	35
PCT	42	28	26
PCT	27	19	21
PCT	22	25	25
PCT	26	—	—