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between 16 and 65 years. The final sample included 18 males and 27
females who ranged in age from 18 to 60 years (
M
¼
30.38,
SD
¼
10.79).
Twenty-two participants were motor-vehicle-accident survivors and 23
were nonsexual-assault victims.
Procedure
After description of the study, participants’ written informed con-
sent was obtained. The first assessment involved the administration of
the Acute Stress Disorder Interview (ASDI; Bryant, Harvey, Dang, &
Sackville, 1998), which is a structured clinical interview that contains 19
dichotomously scored items that relate to ASD symptoms. The ASDI
possesses sound test-retest reliability between 1 and 3 weeks interval
(
r
¼
.95), sensitivity (91%), and specificity (93%) relative to independent
clinician diagnoses (26). To index the range of reexperiencing, avoid-
ance, and hyperarousal symptoms in PTSD, participants were also
administered the Impact of Event Scale (IES; Horowitz, Wilner, &
Alvarez, 1979) and the Beck Anxiety Inventory (BAI; Beck & Steer,
1990). Between 1 and 3 days later, participants were administered the
Stanford Hypnotic Clinical Scale (SHCS; Morgan &Hilgard, 1978–1979)
by an independent clinical psychologist who was blind to the diag-
nostic status of the participant. The SHCS is a standardized assessment
of hypnotic susceptibility that involves a hypnotic induction, followed
by five hypnotic suggestions (hand lowering, age regression, dream,
posthypnotic suggestion, and posthypnotic amnesia). The SHCS is
normally distributed and correlates strongly with established measures
of hypnotizability (e.g.,
r
¼
.72 with the Stanford Hypnotic Suscep-
tibility Scale, FormC; Weitzenhoffer &Hilgard, 1963). Participants were
informed that the SHCS was being administered in order to assist ‘‘our
understanding of how trauma influences how people think and feel.’’
Participants were then provided with cognitive-behavior therapy for
six sessions. Therapy involved education about trauma, anxiety man-
agement, exposure, and cognitive therapy. Half the participants also
received a hypnotic induction prior to exposure (for full details, see
Bryant, Moulds, Guthrie, & Nixon, in press). Six months following
treatment, participants were assessed with the Clinician Administered
PTSD Scale, Form 2 (CAPS-2; Blake et al., 1995) to assess for PTSD, as
well as the IES and BAI. Participants were also re-assessed with the
SHCS by a clinical psychologist who was blind to participants’ treat-
ment status.
R
ESULTS
Preliminary Analyses
All participants met criteria for ASD at the initial assessment, and the
mean SHCS score at the initial assessment was 3.24 (
SD
¼
1.35). At the
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RICHARD A. BRYANT ET AL.
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