Acute Stress Disorder
Acute Stress Disorder
What is Acute Stress Disorder (ASD)?
Acute Stress Disorder, or ASD, is a psychiatric diagnosis that was introduced into the DSM-IV in 1994. The current diagnostic criteria for ASD are similar to the criteria for PTSD, although the criteria for ASD contain a greater emphasis on dissociative symptoms and the diagnosis can only be given within the first month after a traumatic event. The inclusion of ASD in the DSM-IV was not accompanied by extensive research, and some debate exists regarding whether the diagnostic criteria accurately reflect pathological reactions to trauma that occur within the first month after a trauma (1). However, even though debate exists about the empirical basis of the diagnosis, it has been found to be highly predictive of subsequent PTSD.
How common Is ASD?
Studies of ASD have utilized a variety of measurement tools with varying degrees of reliability and validity. The following rates should be interpreted with some caution, and it is possible that rates will change as measures for ASD become more uniform among researchers.
Studies of motor vehicle accident (MVA) survivors have found rates of ASD ranging from approximately 13% (2-3) to 21% (4). A study of survivors of a typhoon revealed an ASD rate of 7% (5), while a study of survivors of an industrial accident revealed a rate of 6% (6). A rate of 19% was found in survivors of violent assault (7) while a rate of 13% was found in a mixed group consisting of survivors of assaults, burns, and industrial accidents (8). A study of victims of robbery and assault found that 25% met criteria for ASD (9), while a study of victims of a mass shooting found that 33% met criteria (10).
A study that used PTSD criteria and evaluated rape survivors within the first month of a trauma revealed a prevalence rate of 94% (11). This last study evaluated PTSD diagnostic criteria during the first month after a trauma. Therefore, it did not assess for the presence of dissociative symptoms that are specific to the diagnosis of ASD (but not PTSD). However, the study (11) is included here to give the reader a sense of the level of posttraumatic sequelae that may be expected after sexual assault.
Who is at risk for ASD resulting from trauma?
While many studies have examined factors that place individuals at risk for developing PTSD, only a handful of studies have examined risk factors for the development of ASD. One retrospective study (12) found that individuals with exposure to prior trauma, individuals with prior PTSD, and individuals with more psychiatric dysfunction were all more likely to develop ASD when confronted with a new traumatic stressor. Bryant and Harvey (1) report that in their sample of motor vehicle accident (MVA) survivors without head injuries, there were several strong predictors of ASD severity: depression score, history of psychiatric treatment, history of PTSD, and prior motor vehicle accidents. These predictors accounted for 61% of the variance. There is also some evidence that individuals prone to experiencing dissociation in the face of traumatic stressors may be more likely to develop ASD (13).
How do PTSD and ASD differ?
ASD and PTSD differ in two fundamental ways. The first difference is that the diagnosis of ASD can be given only within the first month following a traumatic event. If posttraumatic symptoms were to persist beyond a month, the clinician would assess for the presence of PTSD. The ASD diagnosis would no longer apply.
ASD also differs from PTSD in that it includes a greater emphasis on dissociative symptoms. An ASD diagnosis requires that a person experience three symptoms of dissociation (e.g., numbing, reduced awareness, depersonalization, derealization, or amnesia), while the PTSD diagnosis does not include a dissociative symptom cluster. Please see Bryant and Harvey's comprehensive text on ASD (1) for a thorough discussion of the differences between ASD and PTSD.
How predictive of PTSD is ASD?
A diagnosis of ASD, in the absence of treatment, appears to be an accurate predictor of subsequent PTSD. Harvey and Bryant (3) found that 78% of MVA survivors who initially met criteria for ASD met criteria for PTSD six months post trauma. In a similar study of MVA survivors with mild traumatic brain injury, 82% of those initially diagnosed with ASD met criteria for PTSD six months post trauma (14). Brewin et al. (7) found that 83% of assault victims who initially met criteria for ASD met criteria for PTSD at a 6-month follow-up.
Bryant and Harvey (1) note that while ASD is highly predictive of subsequent PTSD, subthreshold ASD (which is typically ASD without the dissociative symptoms) is also a good predictor of PTSD. This suggests that the ASD criteria do not adequately capture all individuals who are at risk for developing full-blown PTSD. The reason for this appears to be that some individuals at risk for PTSD do not develop acute dissociative symptoms and therefore do not ever meet criteria for ASD. Research is currently underway regarding the different trajectories that individuals follow in the development of PTSD.
How is ASD diagnosed?
There are few well-established and empirically-validated measures to assess ASD. Although a comprehensive review of assessment measures is beyond the scope of this fact sheet, the tools with the strongest psychometric properties are described below:
Both scales may be found in Bryant and Harvey's text on ASD (1).
Are there effective treatments for ASD?
Cognitive behavioral interventions
At present, cognitive behavioral interventions during the acute aftermath of trauma exposure have yielded the most consistently positive results in terms of preventing subsequent posttraumatic psychopathology. Four out of five randomized clinical trials (RCTs)(17-20) related to early cognitive behavioral interventions during the acute aftermath of trauma found that the Cognitive Behavioral Therapy (CBT) group experienced a greater reduction of PTSD symptoms than comparison groups. One of the RCTs (21) did not find this to be true. That study (21) found that all three active conditions (desensitization, hypnotherapy, and psychodynamic therapy) yielded equal improvement relative to the waitlist control group. However, the study lacked a treatment adherence measure, so it is unclear whether the CBT intervention was implemented in a standardized manner relative to other studies of CBT.
A different controlled (but not randomized) study (22) compared a CBT intervention to an assessment-only condition during the acute phase post trauma. Fewer PTSD symptoms were found in the CBT group at a 5.5-month follow-up.
Bryant and colleagues (15, 19) have conducted the only studies that specifically assessed and treated ASD. They have shown that a brief cognitive behavioral treatment may not only ameliorate ASD, but it may also prevent the subsequent development of PTSD. Approximately 10 days after exposure to a MVA, industrial accident, or nonsexual assault, Bryant and colleagues randomly assigned those with ASD to five individual, 1.5-hour sessions of either a cognitive behavioral treatment or a supportive counseling control condition. They found that fewer CBT subjects met criteria for PTSD post treatment and 6 months later.
In the 1999 study, Bryant and colleagues compared two different individual CBT approaches (prolonged exposure plus anxiety management and prolonged exposure alone) to a supportive counseling intervention. They found that both CBT groups showed significantly greater reductions in PTSD symptom severity compared to the supportive counseling group.
Psychological debriefing is an early intervention that was originally developed for rescue workers that has been more widely applied in the acute aftermath of potentially traumatic events. However, RCTs of debriefing have yielded inconsistent findings in terms of its efficacy. A review of the literature on debriefing RCTs (23) concluded that there is little evidence to support the continued use of debriefing with acutely traumatized individuals.
Mitchell and Everly (24), the originators of the debriefing model, have made the cogent argument that most of the debriefing RCTs to date have studied only one component (debriefing) of the longer-term and more comprehensive Critical Incident Stress Management model. It is possible that this more comprehensive intervention would prove efficacious, but to date no RCTs have been conducted using the full intervention.
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