Basic HTML Version
limitation with all previous studies of hypnotizability and clinical
disorders is that assessment of hypnotizability occurs cross-sectionally.
Accordingly, there is a lack of evidence indicating the stability of
hypnotizability levels in people with a clinical disorder.
Individuals with acute stress disorder (ASD) represent a useful
population in which to study hypnotizability. The ASD diagnosis
describes people who are recently exposed to trauma and display
dissociative, reexperiencing, avoidance, and hyperarousal symptoms
(Harvey & Bryant, 2002). Importantly, to meet criteria for ASD, one
must display at least three dissociative symptoms (Spiegel, Koopman,
Carden˜ a, & Classen, 1996). Prospective studies have indicated that
approximately 80% of people who meet criteria for ASD subsequently
develop chronic PTSD (for a review, see Bryant, in press). We have
previously reported that people with ASD have markedly higher
levels of hypnotizability than people recently exposed to trauma
who don’t have ASD (Bryant, Moulds, & Guthrie, 2001). Although
we interpreted this finding as being consistent with the proposal that
people with an aptitude for dissociative tendencies may develop a
dissociative disorder following stress, the cross-sectional nature of that
study did not address other possibilities. It is possible that hypnotiz-
ability levels may be influenced by the recentness of trauma exposure
or by the symptoms associated with ASD, including the requisite
dissociative symptoms.
To address this issue, we conducted a prospective study of hypno-
tizability levels in individuals with ASD prior to receiving therapy and
6 months following therapy. All participants were administered a
hypnotic susceptibility scale prior to treatment and within 1 month
of their trauma. Participants then received six sessions of cognitive-
behavior therapy. Six months following therapy, participants were
readministered a hypnotic susceptibility scale. On the basis that hyp-
notizability levels remain stable across time (Piccione, Hilgard, &
Zimbardo, 1989), we predicted that hypnotizability would not change
across assessments.
M
ETHOD
Participants
Forty-five survivors of nonsexual assault or motor vehicle accidents
were referred to the PTSD Unit at Westmead Hospital for treatment
within 1 month of trauma exposure. Inclusion criteria included (a)
meeting criteria for acute stress disorder, (b) ability to comprehend all
interview questions without the aid of an interpreter, (c) no evidence of
traumatic brain injury, (d) no prescription of narcotic analgesia (with
the exception of codeine) for the first 4 weeks posttrauma, and (e) aged
PTSD AND HYPNOTIZABILITY
383
Downloaded by [ ] at 04:41 26 March 2012