Volume 10, Number 5, 2007
© Mary Ann Liebert, Inc.
Comparing Acceptance and Refusal Rates of Virtual
Reality Exposure vs. In Vivo Exposure by Patients
with Specific Phobias
A. GARCIA-PALACIOS, Ph.D.,
C. BOTELLA, Ph.D.,
H. HOFFMAN, Ph.D.,
and S. FABREGAT, B.A.
The present survey explored the acceptability of virtual reality (VR) exposure and in vivo ex-
posure in 150 participants suffering from specific phobias. Seventy-six percent chose VR over
in vivo exposure, and the refusal rate for in vivo exposure (27%) was higher than the refusal
rate for VR exposure (3%). Results suggest that VR exposure could help increase the number
of people who seek exposure therapy for phobias.
HOBIAS ARE SOME
of the most common mental dis-
In vivo exposure therapy is considered
the treatment of choice for phobias. This interven-
tion has received wide empirical support from nu-
merous clinical trials.
The American Psychological
Association (APA) report on empirically supported
treatments included exposure-based treatment
manuals for specific and social phobia.
excellent efficacy data supporting in vivo exposure,
it unfortunately presents some limitations. Most
people who suffer phobias (around 60–80%) never
and of those who do seek treat-
ment, approximately 25% either refuse exposure
therapy when they hear what it entails or drop out
One of the reasons for this refusal data
could be that the main feature of exposure is con-
fronting the feared stimuli, which some people may
find too frightening. New efforts are needed to in-
crease the number of phobia sufferers who benefit
from exposure therapy.
Some preliminary data from a nonclinical sample
supports the acceptability of VR exposure versus in
vivo exposure. Garcia-Palacios et al.
undergraduate students who scored high in a fear
of spiders questionnaire. Participants strongly pre-
ferred VR exposure treatment to in vivo exposure
therapy. This work provided preliminary data
about the preference of VR exposure to in vivo ex-
posure in a nonclinical sample.
The aim of the present work is to conduct a sur-
vey to explore whether people with phobias would
prefer VR exposure to in vivo exposure in a clinical
sample of people suffering specific phobias and spe-
cific social phobias (fear of public speaking).
Universitat Jaume I, Castelló de la Plana, Spain.
Human Interface Technology Laboratory. University of Washington, Seattle, Washington.
Ciber Fisiopatologia Obesidad y Nutricion Instituto de Salud Carlos III, Spain.
The sample included 150 participants in two dif-
ferent samples who participated in different clinical
trials exploring the effectiveness of VR exposure in
the treatment of specific phobias. Some of the par-
ticipants (25, or 16.7%) belonged to a sample re-
cruited from the University of Washington in the
United States. Most of the participants (125, or
83.3%) were recruited from Universitat Jaume I in
Spain. The sample was composed of 73 people
(48.7%) diagnosed with specific phobias: animal
phobias (spiders, cockroaches, rats); 18 people (12%)
were diagnosed with a situational phobia (claus-
trophobia); 6 people (4%) were diagnosed with a
natural environment phobia (heights); and finally,
53 people (35.3%) were diagnosed with social pho-
bia (discrete subtype: fear of public speaking). Most
of the participants were women (86%). The mean
age of the participants was 27.43 years (SD 9.71)
ranging from 18 to 69; and 62.7% had an university
degree or were studying for a university degree,
30.6% had a high school education, and 6.7% had
an elementary school education.
Anxiety Disorders Interview Schedule (ADIS-IV).
We used different adaptations of the Behavioral
Avoidance Test (BAT) for the various fears. See Gar-
cia-Palacios et al.
for a description of the BAT for
specific phobia, animal type, and Botella et al.
description of the BAT for claustrophobia. The BAT
for specific phobia, natural environment type
(heights), is an adaptation from Menzies and Clarke.
Finally, we used the BAT developed by Beidel et al.
for specific social phobia Self-report instruments in-
cluded a fear of spiders questionnaire, (FSQ,)
an in vivo versus VR exposure questionnaire.
Participants belonging to the United States sam-
ple were recruited from mass testing in an intro-
ductory psychology class. Participants completed
the FSQ. People scoring over 2 standard deviations
above the class mean in fear of spiders were invited
to participate in the study. Participants belonging to
the Spanish sample were recruited at Universitat
Jaume I through advertisements in the university
and local journals and posters around campus. The
criteria to participate in the study were as follows:
1. Meet DSM-IV
criteria for specific phobia or so-
cial phobia (fear of public speaking) according
to the judgment of two clinical psychologists, us-
ing the ADIS-IV interview.
2. Have a minimum of one-year duration of the
3. Be unable to complete a BAT.
4. Have no current alcohol or drug dependence.
5. Have no severe physical illness.
6. Read and sign a consent form previously ap-
proved by an Internal Review Board.
During the assessment, participants read and
completed the in vivo versus VR exposure ques-
tionnaire. This was done before starting the assess-
ment process and before they knew which treatment
they would receive. For example, participants re-
cruited at mass testing read the explanation and an-
swered the questions at mass testing; those coming
to the clinic directly did it in the first assessment
session before starting the diagnostic interview.
Results (on a scale from 1 to 7) showed that par-
ticipants were more willing to participate in a VR ex-
posure program (M 6.08, SD 1.31) than in an in
vivo exposure treatment (M 3.97, SD 1.89). The
difference between the means was statistically signif-
icant, t(149) 13.807, p 0.001. We also studied the
percentage of participants who refused to go through
the two different exposure programs: 27% refused in
vivo exposure, and 3% refused VR exposure. Using a
stricter definition of refusal, 14% of the participants
completely refused in vivo exposure, whereas none
of the participants completely refused VR exposure.
Regarding the preference between the two kinds
of exposure, 76% chose VR exposure, and 23.7%
chose in vivo exposure. We performed a binomial
test that showed that the difference between the per-
centage who chose in vivo and the percentage who
chose VR was statistically significant (p 0.001).
Most of those who chose VR exposure (90.4%)
said they chose it because they were too afraid of
confronting the real feared objects or situations.
Some (4.1%) chose VR because they thought it was
attractive and innovative; another 4.1% because
they thought it would be more difficult to control
real spiders; and 1.4% gave other reasons. On the
other hand, most of those who chose in vivo (57.7%)
said they chose this option because they considered
that “it is necessary to confront real spiders to over-
come the fear”; 23.1% chose in vivo because “the
computer-generated spiders won’t be able to make
me believe that I’m confronting real spiders.” Fi-
nally, 19.2% chose in vivo because “new technolo-
gies provoke distress in me.”
VR EXPOSURE VS. IN VIVO EXPOSURE
The present study provides the first clinical data
comparing acceptance of VR exposure vs. in vivo
exposure by participants suffering phobias. These
results support the use of VR exposure with the aim
to increase the acceptability of one of the most effi-
cacious techniques in clinical psychology: exposure
The research presented in this paper was funded
by Ministerio de Ciencia y Tecnología, grant
TIC2000-0184-P4-03, and Pla de Promocio de la In-
vestigacio, Fundacio Caixa Castello-Bancaixa 1999,
2000, and Ministerio de Educación y Ciencia, Spain.
Proyectos Consolider-C (SEJ2006-14301/PSIC).
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Address reprint requests to:
Dr. Azucena Garcia-Palacios
Universitat Jaume I
Dpt. Psicologia Basica
Clinica y Psicobiologia
Avda Vicent Sos Baynat, s/n
12071 Castelló de la Plana, Spain
GARCIA-PALACIOS ET AL.