Diagnostic Features
The essential feature of Acute Stress Disorder is the development of characteristic anxiety, dissociative, and other symptoms that occurs within 1 month after exposure to an extreme traumatic stressor (Criterion A). For a discussion of the types of stressors involved, see the description of Posttraumatic Stress Disorder. Either while experiencing the traumatic event or after the event, the individual has at least three of the following dissociative symptoms: a subjective sense of numbing, detachment, or absence of emotional responsiveness; a reduction in awareness of his or her surroundings; derealization; depersonalization; or dissociative amnesia (Criterion B). Following the trauma, the traumatic event is persistently reexperienced (Criterion C), and the individual displays marked avoidance of stimuli that may arouse recollections of the trauma (Criterion D) and has marked symptoms of anxiety or increased arousal (Criterion E). The symptoms must cause clinically significant distress, significantly interfere with normal functioning, or impair the individual’s ability to pursue necessary tasks (Criterion F). The disturbance lasts for a minimum of 2 days and a maximum of 4 weeks after the traumatic event (Criterion G); if symptoms persist beyond 4 weeks, the diagnosis of Posttraumatic Stress Disorder may be applied. The symptoms are not due to the direct physiological effects of a substance (i.e., a drug of abuse, a medication) or a general medical condition, are not better accounted for by Brief Psychotic Disorder, and are not merely an exacerbation of a preexisting mental disorder (Criterion H).

As a response to the traumatic event, the individual develops dissociative symptoms. Individuals with Acute Stress Disorder may have a decrease in emotional responsiveness, often finding it difficult or impossible to experience pleasure in previously enjoyable activities, and frequently feel guilty about pursuing usual life tasks. They may experience difficulty concentrating, feel detached from their bodies, experience the world as unreal or dreamlike, or have increasing difficulty recalling specific details of the traumatic event (dissociative amnesia). In addition, at least one symptom from each of the symptom clusters required for Posttraumatic Stress Disorder is present. First, the traumatic event is persistently reexperienced (e.g., recurrent recollections, images, thoughts, dreams, illusions, flashback episodes, a sense of reliving the event, or distress on exposure to reminders of the event). Second, reminders of the trauma (e.g., places, people, activities) are avoided. Finally, hyperarousal in response to stimuli reminiscent of the trauma is present (e.g., difficulty sleeping, irritability, poor concentration, hypervigilance, an exaggerated startle response, and motor restlessness).

Associated Features and Disorders
Associated descriptive features and mental disorders. Symptoms of despair and hopelessness may be experienced in Acute Stress Disorder and may be sufficiently severe and persistent to meet criteria for a Major Depressive Episode, in which case an additional diagnosis of Major Depressive Disorder may be warranted. If the trauma led to another’s death or to serious injury, survivors may feel guilt about having remained intact or about not providing enough help to others. Individuals with this disorder often perceive themselves to have greater responsibility for the consequences of the trauma than is warranted. Problems may result from the individual’s neglect of basic health and safety needs associated with the aftermath of the trauma. Individuals with this disorder are at increased risk for the development of Posttraumatic Stress Disorder. Rates of Posttraumatic Stress Disorder of approximately 80% have been reported for motor vehicle crash survivors and victims of violent crime whose response to the trauma initially met criteria for Acute Stress Disorder. Impulsive and risk-taking behavior may occur after the trauma.

Associated physical examination findings and general medical conditions. General medical conditions may occur as a consequence of the trauma (e.g., Head injury, burns).

Specific Culture Features
Although some events are likely to be universally experienced as traumatic, the severity and pattern of response may be modulated by cultural differences in the implications of loss. There may also be culturally prescribed coping behaviors that are characteristic of particular cultures. For example, dissociative symptoms may be a more prominent part of the acute stress response in cultures in which such behaviors are sanctioned.

Prevalence
The prevalence of Acute Stress Disorder in a population exposed to a serious traumatic stress depends on the severity and persistence of the trauma and the degree of exposure to it. The prevalence of Acute Stress Disorder in the general population is not known. In the few available studies, rates ranging from 14% to 33% have been reported in individuals exposed to severe trauma (i.e., being in a motor vehicle accident, being a bystander at a mass shooting).

Course
Symptoms of Acute Stress Disorder are experienced during or immediately after the trauma, last for at least 2 days, and either resolve within 4 weeks after the conclusion of the traumatic event or the diagnosis is changed. When symptoms persist beyond 1 month, a diagnosis of Posttraumatic Stress Disorder may be appropriate if the full criteria for Posttraumatic Stress Disorder are met. The severity, duration, and proximity of an individual’s exposure to the traumatic event are the most important factors in determining the likelihood of development of Acute Stress Disorder. There is some evidence that social supports, family history, childhood experiences, personality variables, and preexisting mental disorders may influence the development of Acute Stress Disorder. This disorder can develop in individuals without any predisposing conditions, particularly if the stressor is especially extreme.

Differential Diagnosis
Some symptomatology following exposure to an extreme stress is ubiquitous and often does not require any diagnosis. Acute Stress Disorder should only be considered if the symptoms last at least 2 days and cause clinically significant distress or impairment in social, occupational, or other important areas of functioning or impair the individual’s ability to pursue some necessary task (e.g., obtaining necessary assistance or mobilizing personal resources by telling family members about the traumatic experience).

Acute Stress Disorder must be distinguished from a Mental Disorder Due to a General Medical Condition (e.g., head trauma) and from a Substance-Induced Disorder (e.g., related to Alcohol Intoxication), which may be common consequences of exposure to an extreme stressor. In some individuals, psychotic symptoms may occur following an extreme stressor. In such cases, Brief Psychotic Disorder is diagnosed instead of Acute Stress Disorder. If a Major Depressive Episode develops after the trauma, a diagnosis of Major Depressive Disorder should be considered in addition to a diagnosis of Acute Stress Disorder. A separate diagnosis of Acute Stress Disorder should not be made if the symptoms are an exacerbation of a preexisting mental disorder.

By definition, a diagnosis of Acute Stress Disorder is appropriate only for symptoms that occur within 1 month of the extreme stressor. Because Posttraumatic Stress Disorder requires more than 1 month of symptoms, this diagnosis cannot be made during this initial 1-month period. For individuals with the diagnosis of Acute Stress Disorder whose symptoms persist for longer than 1 month, the diagnosis of Posttraumatic Stress Disorder should be considered. For individuals who have an extreme stressor but who develop a symptom pattern that does not meet criteria for Acute Stress Disorder, a diagnosis of Adjustment Disorder should be considered.

Malingering must be ruled out in those situations in which financial remuneration, benefit eligibility, or forensic determinations play a role.

Diagnostic criteria for Acute Stress Disorder

A. The person has been exposed to a traumatic event in which both of the following were present:
(1) the person experienced, witnessed, or was confronted with an event or events that involved actual or threatened death or serious injury, or a threat to the physical integrity of self or others
(2) the person’s response involved intense fear, helplessness, or horror

B. Either while experiencing or after experiencing the distressing event, the individual has three (or more) of the following dissociative symptoms:
(1) a subjective sense of numbing, detachment, or absence of emotional responsiveness
(2) a reduction in awareness of his or her surroundings (e.g., “being in a daze”)
(3) derealization
(4) depersonalization
(5) dissociative amnesia (i.e., inability to recall an important aspect of the trauma)

C. The traumatic event is persistently reexperienced in at least one of the following ways: recurrent images, thoughts, dreams, illusions, flashback episodes, or a sense of reliving the experience; or distress on exposure to reminders of the traumatic event.
D. Marked avoidance of stimuli that arouse recollections of the trauma (e.g., thoughts, feelings, conversations, activities, places, people).
E. Marked symptoms of anxiety or increased arousal (e.g., difficulty sleeping, irritability, poor concentration, hypervigilance, exaggerated startle response, motor restlessness).
F. The disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning or impairs the individual’s ability to pursue some necessary task, such as obtaining necessary assistance or mobilizing personal resources by telling family members about the traumatic experience.
G. The disturbance lasts for a minimum of 2 days and a maximum of 4 weeks and occurs within 4 weeks of the traumatic event.
H. The disturbance is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition, is not better accounted for by Brief Psychotic Disorder, and is not merely an exacerbation of a preexisting Axis I or Axis II disorder.