Content uploaded by Catherine C Classen
Author content
All content in this area was uploaded by Catherine C Classen
Content may be subject to copyright.
Am J Psychiatry 155:5, May 1998CLASSEN, KOOPMAN, HALES, ET AL.ACUTE STRESS DISORDER
Acute Stress Disorder
as a Predictor of Posttraumatic Stress Symptoms
Catherine Classen, Ph.D., Cheryl Koopman, Ph.D.,
Robert Hales, M.D., and David Spiegel, M.D.
Objective: Using the DSM-IV diagnostic criteria for acute stress disorder, the authors ex-
amined whether the acute psychological effects of being a bystander to violence involving mass
shootings in an office building predicted later posttraumatic stress symptoms.
Method: The
participants in this study were 36 employees working in an office building where a gunman
shot 14 persons (eight fatally). The acute stress symptoms were assessed within 8 days of the
event, and posttraumatic stress symptoms of 32 employees were assessed 7 to 10 months later.
Results: According to the Stanford Acute Stress Reaction Questionnaire, 12 (33%) of the
employees met criteria for the diagnosis of acute stress disorder. Acute stress symptoms were
found to be an excellent predictor of the subjects’ posttraumatic stress symptoms 7–10 months
after the traumatic event.
Conclusions: These results suggest not only that being a bystander
to violence is highly stressful in the short run, but that acute stress reactions to such an event
further predict later posttraumatic stress symptoms.
(Am J Psychiatry 1998; 155:620–624)
A
cute stress disorder is a new psychiatric diagnosis
in DSM-IV that includes a set of symptoms experi-
enced by some individuals shortly after a traumatic event.
To be diagnosed as suffering from acute stress disorder
the individual must exhibit at least three dissociative
symptoms along with at least one intrusion, avoidance,
and hyperarousal symptom. In addition, the symptoms
must cause clinically significant difficulties in functioning
and persist 2–28 days. Also, the reaction must not be due
to the ingestion of substances or to a general medical con-
dition or be attributable to a brief psychotic disorder or
a preexisting axis I or axis II disorder.
This diagnosis is based on a large body of research
dating back to Lindemann’s classic paper (1) in which
he described survivors’ immediate reactions to the Co-
conut Grove fire. Since Lindemann’s observations there
have been numerous studies that have reports of disso-
ciative, avoidance, and hyperarousal symptoms shortly
after traumatic experiences (2–10). The specific diag-
nostic criteria for acute stress disorder were based on
empirical evidence from studies that systematically
documented acute stress reactions in response to trau-
matic events (2–4, 7).
The scientific basis for the diagnostic category of acute
stress disorder was also justified by research showing that
dissociative reactions immediately after a traumatic ex-
perience predicted later posttraumatic stress disorder
(PTSD) symptoms (2–4, 7, 11–14). These studies were
conducted before the final definition of acute stress dis-
order and its inclusion in DSM-IV and, therefore, did not
include a systematic assessment of all acute stress disor-
der symptoms and their relationship with later PTSD
symptoms. To our knowledge, no published research has
systematically examined the relationship between acute
stress disorder and PTSD symptoms, despite the assump-
tion stated in DSM-IV that acute stress disorder can lead
to PTSD. Therefore, we conducted a study to examine
the relationship between acute stress disorder symptoms
and PTSD symptoms.
Along with documenting the relationship between
acute stress disorder symptoms and PTSD symptoms,
in the present study we examined this relationship
within the context of two other factors, gender and de-
gree of exposure to the traumatic event. Gender has
been shown to be associated with acute stress reactions
(15) and PTSD symptoms (16–19), with women report-
ing the most symptoms. Degree of exposure to the trau-
matic event has been found to be associated with the
level of symptoms following a traumatic event (7, 8, 14,
19–26), although in one anecdotal study no such rela-
tionship was found (27).
Received March 25, 1996; revisions received Feb. 19 and July 11,
1997; accepted Sept. 18, 1997. From the Department of Psychiatry
and Behavioral Sciences, Stanford University School of Medicine, and
the Department of Psychiatry, University of California, Davis. Ad-
dress reprint requests to Dr. Classen, Department of Psychiatry and
Behavioral Sciences, Stanford University School of Medicine, Stan-
ford, CA 94305-5718; classen@leland.stanford.edu (e-mail).
Supported by grants from the John D. and Catherine T. MacArthur
Foundation and the American Psychiatric Association.
The authors thank Ami Atkinson, John Mori, and the persons who
participated in the study.
620 Am J Psychiatry 155:5, May 1998
The hypotheses in this study were as follows: 1) meet-
ing all of the symptom criteria for acute stress disorder
would predict subsequent PTSD symptoms, 2) women
would be more likely than men to exhibit PTSD symp-
toms, and 3) degree of exposure to the threat would be
positively associated with PTSD symptoms. Along with
gender, other demographic variables (education and
marital status) were included in the analyses in order to
control for their contribution to the development of
PTSD symptoms.
The traumatic incident examined was the shooting of
persons by a gunman in an office building where the
respondents in this study worked. Unfortunately, such
events are not rare. In 1993, a thousand employees in
the United States were murdered at their places of work
(28). Research suggests that persons who are bystand-
ers, such as other employees, are deeply affected by
these events. Several studies have examined stress reac-
tions to being a bystander to shootings (24, 29–31).
These studies indicated that acute stress reactions to
such an event are normal. Nevertheless, some individu-
als may exhibit more extreme reactions to the event,
warranting a diagnosis of acute stress disorder in the
immediate aftermath, and may later experience post-
traumatic stress symptoms.
We conducted a study of employees working in an
office building where a shooting spree occurred during
the workday. We examined their acute stress reactions
in the immediate aftermath of this event. Their post-
traumatic stress symptoms were assessed 7 to 10 months
later.
METHOD
The Traumatic Event
On the afternoon of Thursday, July 1, 1993, 14 persons were shot
on two floors and in the stairwell of a high-rise office building at 101
California Street in San Francisco. Eight persons, including the gun-
man, were shot fatally. Many employees were trapped inside the
building for hours while police officers tried to stop the gunman, and
there were rumors that there were at least two gunmen on the loose.
Within 8 days after the shootings, 36 employees from two firms on
nearby floors of the building attended a crisis intervention session and
completed questionnaires about their acute distress symptoms and
other reactions.
Study Group
After obtaining permission from our institutional human subjects
review committee to perform this study, we were granted permission
from two firms to meet with their employees to offer a crisis interven-
tion session and to seek their participation in this study. Before the
intervention and data collection, the subjects were fully informed re-
garding the crisis intervention and the data collection. They were in-
vited to participate in the intervention session and were told that their
participation in the intervention in no way obligated them to partici-
pate in the study. The intervention took approximately 1 hour and
consisted of inviting the employees to describe the thoughts and feel-
ings they had had both during and after the traumatic event, provid-
ing a brief overview of common reactions to trauma as a way of nor-
malizing their experience, providing suggestions for what they could
do to help themselves integrate the experience and then move on in
their lives, and describing how to determine whether they required
professional help.
After the crisis intervention session, the study was introduced, the
procedure of the study was fully explained, and the employees were
again reminded that they were under no obligation to participate.
Written informed consent was received, and the questionnaires were
distributed; 36 employees completed the questionnaires. All worked
in the office building where the shootings occurred; 26 worked in one
firm and 10 worked in another. All questionnaires were completed
within 8 days after the shootings. A follow-up assessment was mailed
to the participants 7 months later, and follow-up mailings and phone
calls were conducted to encourage willing participants to complete
this follow-up assessment. Of the 36 persons who participated in the
original assessment, 32 (89%) completed the follow-up assessment.
Measures
Demographic characteristics. The respondents provided demo-
graphic information in a self-report questionnaire. The variables as-
sessed were sex, age, marital status, and years of education.
Ratings of the threatening event. An additive exposure scale as-
sessed the degree of contact that the respondents had with the trau-
matic event. The types of exposure included being in the office build-
ing at the time of the shooting and seeing the S.W.A.T. (police
tactical) team. None of the subjects saw the gunman or his victims.
The respondents were asked to indicate whether they had experienced
each of these forms of exposure to the event. Exposure was scored as
0 if the respondent was not in the building at the time, 1 if the respon-
dent was in the building but did not see the S.W.A.T. team, and 2 if
the respondent was in the building and saw the S.W.A.T. team.
The respondents were asked to rate how disturbing their experi-
ence with this event was, on a scale of 0–10, where 0 represented “not
at all disturbing” and 10 indicated “extremely disturbing.”
Stanford Acute Stress Reaction Questionnaire. This self-report
measure asks the respondent to indicate the frequency with which he
or she experiences a variety of symptoms during or after a stressful
event. Versions of this measure have been used in studies that have
assessed acute reactions to an earthquake (2), witnessing an execution
(4), and a firestorm (7). This version of the Stanford Acute Stress
Reaction Questionnaire assessed four types of symptoms matching
the criteria for a diagnosis of acute stress disorder: dissociation (nine
items, e.g., “I experienced myself as though I were a stranger”); hy-
perarousal (five items, e.g., “I felt hypervigilant or on edge”); reex-
periencing the traumatic event (six items, e.g., “I had repeated and
unwanted memories of the shootings”); and avoidance of reminders
of the traumatic event (two items, e.g., “I tried to avoid activities or
situations that reminded me of the shootings”). Internal consistency
for this group of subjects, based on Cronbach’s alpha, was high over-
all (0.93) and also for the particular symptom subscales of the ques-
tionnaire (0.72–0.88).
Impact of Event Scale. The Impact of Event Scale (32) is a self-re-
port measure assessing the degree of subjective distress experienced
after a stressful life event. In this study, the Impact of Event Scale was
used in the 7-month follow-up assessment as an additional measure
of PTSD symptoms. Individuals were asked to rate the frequency with
which they had had intrusive or avoidant experiences in the 7 days
before assessment. Intrusive experiences include unwanted thoughts,
feelings, or images of the trauma (e.g., “Pictures about it popped into
my mind”). Avoidant experiences include having tried to avoid re-
minders of the trauma or to dull emotional reactions to it (e.g., “I
stayed away from reminders of it”). Internal consistency (Cronbach’s
alpha) for this group was high overall (0.91) and for both subscales
(intrusion=0.89, avoidance=0.88).
Davidson Trauma Scale. The Davidson Trauma Scale (33) was
developed to assess each of the symptoms in DSM-IV needed for a
diagnosis of PTSD. This instrument comprises 17 items inquiring
about frequency and severity of PTSD symptoms within the past
week; frequency is assessed on a 0–4-point scale in which 0 repre-
sents “not at all” and 4 indicates “every day,” and severity is as-
sessed on a 0–4-point scale in which 0 represents “not at all dis-
tressing” and 4 means “extremely distressing.” This instrument is
used to assess PTSD symptoms and has been validated with adult
survivors of childhood sexual abuse (33), rape survivors, and Hur-
CLASSEN, KOOPMAN, HALES, ET AL.
Am J Psychiatry 155:5, May 1998 621
ricane Andrew survivors (Davidson, unpublished manuscript). Its
internal consistency is excellent; the Cronbach’s alpha was 0.91 in
a test with rape survivors. Its criterion validity was evidenced in the
studies of both rape and hurricane survivors, in which the survivors
diagnosed as having PTSD (with the Structured Clinical Interview
for DSM-III-R) had significantly higher mean scores than did the
survivors not meeting the diagnostic criteria for PTSD. Also, this
measure’s concurrent validity is supported by strong correlations
with the scores on the Impact of Event Scale of rape survivors and
with the SCL-90 global severity scores, anxiety subscale scores, and
depression subscale scores of hurricane survivors (Davidson, un-
published manuscript). Internal consistency for this study group
was high (Cronbach’s alpha=0.92). To yield a summary score on
this measure, we tallied the number of symptoms experienced at
least once in the past week (at least twice for recurrent symptoms)
that were minimally to extremely distressing.
Data Analysis
Means, standard deviations, and frequencies were computed to
summarize the distribution of values for each variable. To test the
relationships between PTSD symptoms and the independent vari-
ables, we conducted multiple regression analysis to analyze PTSD
symptoms (assessed as number of symptoms reported on the David-
son Trauma Scale and subscale scores on the intrusion and avoidance
subscales of the Impact of Event Scale) by three blocks of independent
variables, entered hierarchically. In the first block we used the step-
wise forward procedure with the variables of sex, age, years of edu-
cation, and marital status to examine for preexisting demographic
differences that could account for the variance in posttraumatic stress
symptoms. In the second block we again used the stepwise forward
procedure and entered the degree of exposure to the threatening
event, and in the third block we entered whether the respondent met
the symptom criteria for an acute stress disorder diagnosis. Using this
analytic strategy, we were able to examine whether any significant
variance in PTSD symptoms was associated with demographic and
exposure variables before we analyzed the variance in PTSD symp-
toms associated with meeting the criteria for acute stress disorder, the
variable of most interest. To analyze the relationships between spe-
cific symptoms of acute stress disorder and PTSD symptoms, we com-
puted Pearson’s product moment correlations between the four types
of acute stress disorder symptoms (dissociation, hyperarousal, intru-
sion, and avoidance) and the three measures of PTSD symptoms.
RESULTS
Univariate Statistics on Independent
and Dependent Variables
Of the 36 employees, 24 (67%) were women. The
employees ranged in age from 22 to 74 years (mean=
33.2, SD=10.4) and ranged in education from high
school diploma to graduate school, with 80% having
completed college (28 of 35). Their marital status dis-
tribution (N=35) was as follows: single, 54% (N=19);
married, 34% (N=12); and divorced, 11% (N=4).
The majority of the respondents (69%, N=25) were
in the building at the time of the shooting and saw the
S.W.A.T. team, 17% of the respondents (N=6) were
trapped in the building but did not see the S.W.A.T.
team, and 14% (N=5) neither were trapped in the
building nor saw the S.W.A.T. team. None of our sub-
jects actually saw the gunman or the victims.
When asked how disturbing the event was, the re-
spondents gave the event a mean rating of 6.9 (SD=2.6).
This is almost 2 points above 5, which is labeled “mod-
erately disturbing.”
Of the 36 subjects, 12 (33%) met the criteria for the
acute stress disorder diagnosis. The respondents expe-
rienced a mean of 2.0 dissociative symptoms (SD=1.5)
out of a possible 5 symptoms, a mean of 1.3 symptoms
of reexperiencing the traumatic event (SD=1.3) out of
5, a mean of 2.7 symptoms of anxiety and hyperarousal
(SD=1.7) out of 5, and a mean of 1.0 of 2 possible symp-
toms of avoiding reminders of the event (SD=0.9).
At the 7–10-month follow-up assessment, 32 of the
36 respondents completed the questionnaires, although
one of these respondents did not complete the Davidson
Trauma Scale. The respondents’ mean frequency of PTSD
symptoms reported on the Davidson Trauma Scale was
2.5 (SD=3.9) out of a possible 4. Also, the respondents’
mean score at follow-up on the Impact of Event Scale
intrusion subscale was 7.9 (SD=7.8); their mean score
on the avoidance subscale was 8.1 (SD=9.3).
Relation of PTSD Symptoms to Acute Stress Disorder,
Trauma Exposure, and Demographic Characteristics
The overall regression models were significant for
predicting overall posttraumatic stress frequency scores
on the Davidson Trauma Scale (F=5.86, df=1, 27, p<
0.05, adjusted R
2
=0.15), frequency of intrusive symp-
toms as indicated by the intrusion subscale of the Im-
pact of Event Scale (F=30.38, df=1, 28, p<0.0001, ad-
justed R
2
=0.50), and frequency of avoidance symptoms
as indicated by the avoidance subscale of the Impact of
Event Scale (F=21.25, df=1, 28, p<0.0001, adjusted
R
2
=0.41). The results supported the hypothesis that
PTSD symptoms were associated with meeting all of the
symptom criteria for acute stress disorder; however,
PTSD symptoms were not significantly related to expo-
sure to the traumatic event, contrary to our hypothesis.
None of the demographic variables was significantly re-
lated to any of the measures of PTSD symptoms,
thereby providing no support for the hypothesis that
women would be more likely to show PTSD symptoms.
Meeting the criteria for the acute stress disorder diag-
nosis was significantly related to the overall posttrau-
matic stress frequency score on the Davidson Trauma
Scale (B=3.39, SE=1.40, t=2.42, df=1, 27, p<0.05), to
frequency of intrusive symptoms as indicated by the in-
trusion subscale of the Impact of Event Scale (B=11.79,
SE=2.13, t=5.51, df=1, 28, p<0.0001), and to frequency
of avoidance symptoms as indicated by the avoidance
subscale of the Impact of Event Scale (B=12.70, SE=
2.76, t=4.61, df=1, 28, p<0.0001).
Relation of Acute Stress Disorder to PTSD Symptoms
Table 1 shows the Pearson’s product moment corre-
lation coefficients for the association between acute
stress disorder symptoms and PTSD symptoms in re-
sponse to the shootings. All but two of the 15 relation-
ships were statistically significant and in the positive
direction. This showed that three of the four symptoms
included in the acute stress disorder diagnosis (dissocia-
tion, reexperiencing, and avoidance) and the overall di-
ACUTE STRESS DISORDER
622 Am J Psychiatry 155:5, May 1998
agnosis were strongly related to the frequency of expe-
riencing posttraumatic stress symptoms. Hyperarousal
was found to be positively correlated with intrusion,
although it was not significantly correlated with overall
PTSD or avoidance.
DISCUSSION
This study provides evidence that acute stress disorder
predicts PTSD. As hypothesized, individuals who met all
of the symptom criteria for acute stress disorder were
more likely to report PTSD symptoms 7 to 10 months
later. However, neither extent of exposure to the trau-
matic event nor gender was found to predict PTSD symp-
toms. An exploratory analysis showed that three of the
four symptoms included in the acute stress disorder diag-
nosis (dissociation, reexperiencing the traumatic event,
and avoidance) and the overall diagnosis of acute stress
disorder were strongly related to the frequency of expe-
riencing PTSD symptoms. Of these acute stress disorder
symptoms, dissociation in response to the trauma was
found to be one of the strongest predictors of PTSD
symptoms 7 to 10 months later. This suggests that disso-
ciation may be a fundamental symptom of acute stress
disorder. Hyperarousal was found to predict intrusion at
follow-up but not avoidance or overall posttraumatic
stress. This suggests that hyperarousal might be less im-
portant as a predictor of PTSD.
There are several limitations to this study. The main
limitation is that the subjects were not formally diag-
nosed by a clinician as having either acute stress disor-
der or PTSD. Instead, the diagnoses were based on pa-
per-and-pencil measures that were designed to assess
some but not all diagnostic criteria. The measures did
not assess whether the symptoms caused clinically sig-
nificant distress or impairment in functioning, which
is necessary for a formal diagnosis of acute stress disor-
der or PTSD. Also, other diagnoses that may have ac-
counted for the acute stress disorder symptoms were
not ruled out.
The study group in this study was small, the subjects
were not randomly selected, and there was no control
group. The subjects were recruited from two nearby
floors and consisted of individuals who had agreed to
participate after having received a crisis intervention ses-
sion. A larger group of subjects randomly selected from
all floors would have been better. It would have given us
greater power to test our hypotheses, ensured varying de-
grees of exposure, and circumvented the problem of hav-
ing subjects who were self-selected on the basis of their
desire for crisis intervention. Having a control group that
experienced the traumatic event and did not receive an
intervention would have enabled us to also examine the
relationship between acute stress disorder and PTSD
symptoms when there is no intervention.
Our clinical impression was that the debriefing was
experienced as beneficial. The participants appeared re-
lieved to be able to share their experiences with others
and to learn that they were not alone in their reactions.
Several commented on the helpfulness of the interven-
tion. Thus, to the extent that the intervention was effec-
tive, the relationship between acute stress disorder and
PTSD symptoms may be underestimated.
In this study we did not find a relationship between
exposure and PTSD symptoms, and this negative find-
ing might be due to the small number of subjects or to
a restricted range of exposure. Additionally, it may be
because our measure of exposure lacked sensitivity. In
addition, the small number of subjects precluded exam-
ining the role of acute stress disorder relative to other
predictors of PTSD, such as stressful life events (11).
Notwithstanding these limitations, the results suggest
that when individuals experience a traumatic event and
suffer from acute stress disorder, they may also be vul-
nerable to developing PTSD and might benefit from im-
mediate treatment (34–36). Given the role of dissocia-
tion in acute reactions to a traumatic event, affected
individuals are likely to distance themselves from the
event through amnesia, depersonalization, derealiza-
tion, or other means, thereby avoiding the “grief work”
necessary to working through the traumatic experience
and putting it into perspective (1, 37, 38). Sufferers of
acute stress disorder are likely to split off the event from
their experience if untreated.
Thus, individuals who have experienced a traumatic
event should be given the opportunity to process it. The
goals should include normalizing the reactions to the
trauma, providing a safe environment that enables the
expression of strong feelings, enhancing understanding,
and making meaning out of the experience (38, 39).
Another implication of this study is that when indi-
viduals are not directly the targets of violence but ex-
perience only the threat of violence, they too are vul-
nerable to developing acute stress disorder and PTSD.
A full one-third of the individuals in this study met the
symptom criteria for acute stress disorder and were
more likely to develop PTSD symptoms. These were
individuals who never actually saw the gunman, al-
though several individuals stated that they saw a mem-
ber of the S.W.A.T. team and momentarily thought it
TABLE 1. Correlations Between Symptoms of Acute Stress Disorder
and Posttraumatic Stress at 7–10-Month Follow-Up in 32 Subjects
Who Witnessed a Mass Shooting
Acute Stress Disorder
Symptom
a
Correlation With Frequency of
Posttraumatic Stress Symptom (r)
Overall
Posttraumatic
Stress
b
Intrusion
c
Avoidance
c
Dissociation 0.47** 0.58*** 0.61***
Hyperarousal 0.20 0.53** 0.32
Reexperiencing 0.45** 0.73*** 0.49**
Avoidance 0.39* 0.52** 0.49**
All acute stress disor-
der symptoms 0.44** 0.73*** 0.67***
a
Assessed with Stanford Acute Stress Reaction Questionnaire.
b
Assessed with Davidson Trauma Scale; N=31.
c
Assessed with Impact of Event Scale.
*p<0.05. **p≤0.01. ***p≤0.001.
CLASSEN, KOOPMAN, HALES, ET AL.
Am J Psychiatry 155:5, May 1998 623
was the gunman. Nevertheless, there was only the
threat of violence, and it was sufficient for develop-
ment of symptoms.
The results of this study suggest that individuals who
are exposed to violence may develop acute stress disor-
der as a precursor to PTSD symptoms. Given the in-
creasingly violent nature of our society, this puts sub-
stantial numbers of individuals at risk of developing
psychological problems. Given the predictive value of
acute stress disorder symptoms, they provide an oppor-
tunity for early case identification and intervention to
prevent the development of PTSD.
REFERENCES
1. Lindemann E: Symptomatology and management of acute grief.
Am J Psychiatry 1944; 101:141–148
2. Cardeña E, Spiegel D: Dissociative reactions to the San Francisco
Bay Area earthquake of 1989. Am J Psychiatry 1993; 150:474–
478
3. Feinstein A: Posttraumatic stress disorder: a descriptive study
supporting DSM-III-R criteria. Am J Psychiatry 1989; 146:665–
666
4. Freinkel A, Koopman C, Spiegel D: Dissociative symptoms in
media eyewitnesses of an execution. Am J Psychiatry 1994; 151:
1335–1339
5. Hagstrom R: The acute psychological impact on survivors fol-
lowing a train accident. J Trauma Stress 1995; 8:391–402
6. Holen A: The North Sea oil rig disaster, in International Hand-
book of Traumatic Stress Syndromes. Edited by Wilson J, Ra-
phael B. New York, Plenum, 1993, pp 471–478
7. Koopman C, Classen C, Spiegel D: Predictors of posttraumatic
stress symptoms among survivors of the Oakland/Berkeley,
Calif, firestorm. Am J Psychiatry 1994; 151:888–894
8. Nolen-Hoeksema S, Morrow J: A prospective study of depres-
sion and posttraumatic stress symptoms after a natural disaster:
the 1989 Loma Prieta earthquake. J Pers Soc Psychol 1991; 61:
115–121
9. Shalev AY, Peri T, Canetti L, Schreiber S: Predictors of PTSD in
injured trauma survivors: a prospective study. Am J Psychiatry
1996; 153:219–225
10. Ursano RJ, Fullerton CS, Kao TC, Bhartiya VR: Longitudinal
assessment of posttraumatic stress disorder and depression after
exposure to traumatic death. J Nerv Ment Dis 1995; 183:36–42
11. Bremner JD, Southwick SM, Johnson DR, Yehuda R, Charney
DS: Childhood physical abuse and combat-related posttraumatic
stress disorder in Vietnam veterans. Am J Psychiatry 1993; 150:
235–239
12. Marmar CR, Weiss DS, Schlenger WE, Fairbank JA, Jordan BK,
Kulka RA, Hough RL: Peritraumatic dissociation and posttrau-
matic stress in male Vietnam theater veterans. Am J Psychiatry
1994; 151:902–907
13. McFarlane AC: Posttraumatic morbidity of a disaster: a study of
cases presenting for psychiatric treatment. J Nerv Ment Dis
1986; 174:4–14
14. Solomon Z, Mikulincer M, Benbenishty R: Combat stress reac-
tion: clinical manifestations and correlates. Military Psychol
1989; 1:35–47
15. Palinkas LA, Russell J, Downs MA, Petterson JS: Ethnic differ-
ences in stress, coping, and depressive symptoms after the Exxon
Valdez oil spill. J Nerv Ment Dis 1992; 180:287–295
16. Breslau N, Davis GC: Posttraumatic stress disorder in an urban
population of young adults: risk factors for chronicity. Am J Psy-
chiatry 1992; 149:671–675
17. North CS, Smith EM, Spitznagel EL: Posttraumatic stress disor-
der in survivors of a mass shooting. Am J Psychiatry 1994; 151:
82–88
18. Raphael B, Meldrum L: The evolution of mental health responses
and research in Australian disasters. J Trauma Stress 1993; 6:65–
89
19. Hardin SB, Weinrich M, Weinrich S, Hardin TL, Garrison C:
Psychological distress of adolescents exposed to Hurricane
Hugo. J Trauma Stress 1994; 7:427–440
20. Palinkas LA, Petterson JS, Russell J, Downs MA: Community
patterns of psychiatric disorders after the Exxon Valdez oil spill.
Am J Psychiatry 1993; 150:1517–1523
21. Bowler RM, Mergler D, Huel G, Cone JE: Psychological, psy-
chosocial, and psychophysiological sequelae in a community af-
fected by a railroad chemical disaster. J Trauma Stress 1994; 7:
601–624
22. Carlson EB, Rosser-Hogan R: Trauma experiences, posttrau-
matic stress, dissociation, and depression in Cambodian refu-
gees. Am J Psychiatry 1991; 148:1548–1551
23. Mueser KT, Butler RW: Auditory hallucinations in combat-re-
lated chronic posttraumatic stress disorder. Am J Psychiatry
1987; 144:299–302
24. Pynoos RS, Frederick C, Nader K, Arroyo W, Steinberg A, Eth
S, Nunez F, Fairbanks L: Life threat and posttraumatic stress in
school-age children. Arch Gen Psychiatry 1987; 44:1057–1063
25. Sanders B, Giolas MH: Dissociation and childhood trauma in
psychologically disturbed adolescents. Am J Psychiatry 1991;
148:50–54
26. Wood JM, Bootzin RR, Rosenhan D, Nolen-Hoeksema S, Jour-
den F: Effects of the 1989 San Francisco earthquake on fre-
quency and content of nightmares. J Abnorm Psychol 1992; 101:
219–224
27. Hillman RG: The psychopathology of being held hostage. Am J
Psychiatry 1981; 138:1193–1197
28. Martin S: Workplace is no longer a haven from violence. APA
Monitor, October 1994, p 29
29. North CS, Smith EM, McCool RE, Shea JM: Short-term psycho-
pathology in eyewitnesses to mass murder. Hosp Community
Psychiatry 1989; 40:1293–1295
30. Creamer M, Burgess P, Pattison P: Reaction to trauma: a cogni-
tive processing model. J Abnorm Psychol 1992; 101:452–459
31. Sewell JD: Traumatic stress of multiple murder investigations. J
Trauma Stress 1993; 6:103–118
32. Horowitz MJ, Wilner N, Alvarez W: Impact of Event Scale: a
measure of subjective stress. Psychosom Med 1979; 41:209–218
33. Zlotnick C, Davidson J, Shea MT, Perlstein T: The validation of
the Davidson Trauma Scale in a sample of survivors of childhood
sexual abuse. J Nerv Ment Dis 1996; 184:255–257
34. Hoiberg A, McCaughey BG: The traumatic aftereffects of colli-
sion at sea. Am J Psychiatry 1984; 141:70–73
35. Manton M, Talbot A: Crisis intervention after an armed hold-
up: guidelines for counsellors. J Trauma Stress 1990; 3:507–522
36. Spiegel D, Classen C: Acute stress disorder, in Treatment of Psy-
chiatric Disorders, 2nd ed, vol 2. Edited by Gabbard GO. Wash-
ington, DC, American Psychiatric Press, 1995, pp 1521–1535
37. Spiegel D: Vietnam grief work using hypnosis. Am J Clin Hypn
1981; 24:33–40
38. Spiegel D: The use of hypnosis in the treatment of PTSD. Psychia-
try Med 1992; 10:21–30
39. Embry CK: Psychotherapeutic interventions in chronic posttrau-
matic stress disorder, in Posttraumatic Stress Disorder: Etiology,
Phenomenology, and Treatment. Edited by Wolf ME, Mosniam
AD. Washington, DC, American Psychiatric Press, 1990, pp
226–236
ACUTE STRESS DISORDER
624 Am J Psychiatry 155:5, May 1998
