Definition

Acute stress disorder (ASD) is an anxiety disorder characterized by a cluster of dissociative and anxiety symptoms that occur within a month of a traumatic stressor. It is a relatively new diagnostic category and was added to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) in 1994 to distinguish time-limited reactions to trauma from the farther-reaching and longer-lasting post-traumatic stress disorder (PTSD). Published by the American Psychiatric Association, the DSM contains diagnostic criteria, research findings, and treatment information for mental disorders. It is the primary reference for mental health professionals in the United States.

Description

ASD, like PTSD, begins with exposure to an extremely traumatic, horrifying, or terrifying event. Unlike PTSD, however, ASD emerges sooner and abates more quickly; it is also marked by more dissociative symptoms. If left untreated, however, ASD is likely to progress to PTSD. Because the two share many symptoms, some researchers and clinicians question the validity of maintaining separate diagnostic categories. Others explain them as two phases of an extended reaction to traumatic stress.

Causes and symptoms

Causes

The immediate cause of ASD is exposure to trauma—an extreme stressor involving a threat to life or the prospect of serious injury; witnessing an event that involves the death or serious injury of another person; or learning of the violent death or serious injury of a family member or close friend. The trauma's impact is determined by its cause, scope, and extent. Natural disasters (floods, earthquakes, hurricanes, etc.) or accidents (plane crashes, workplace explosions) are less traumatic than human acts of intentional cruelty or terrorism. Terrorist-inflicted trauma appears to produce particularly high rates of ASD and PTSD in survivors and bystanders.

Although most people define trauma in terms of events such as war, terrorist attacks, and other events that result in vast loss of life, the leading cause of stress-related mental disorders in the United States is motor vehicle accidents. Most Americans will be involved in a traffic accident at some point in their lives, and 25% of the population will be involved in accidents resulting in serious injuries. The National Comorbidity Survey of 1995 found that 9% of survivors of serious motor vehicle accidents developed ASD or PTSD.

Several factors influence a person's risk of developing ASD after trauma:

• Age—Older adults are less likely to develop ASD, possibly because they have had more experience coping with painful or stressful events.
• Previous exposure—People who were abused or experienced trauma as children are more likely to develop ASD (or PTSD) as adults, because these may produce long-lasting biochemical changes in the central nervous system.
• Biological vulnerability—Twin studies indicate that certain abnormalities in brain hormone levels and brain structure are inherited, and that these increase a person's susceptibility to ASD following exposure to trauma.
• Support networks—People who have a network of close friends and relatives are less likely to develop ASD.
• Perception and interpretation—People who feel inappropriate responsibility for the trauma, regard the event as punishment for personal wrongdoing, or have generally negative or pessimistic worldviews are more likely to develop ASD than those who do not personalize the trauma or are able to maintain a balanced view of life.

Symptoms

Acute stress disorder may be diagnosed in patients who (A) lived through or witnessed a traumatic event to which they (B) responded with intense fear, horror, or helplessness, and are (C) currently experiencing three or more of the following dissociative symptoms:

• psychic numbing
• being dazed or less aware of surroundings
• derealization
• depersonalization
• dissociative amnesia

Other symptoms that indicate ASD are:

• Reexperiencing the trauma in recurrent dreams, images, thoughts, illusions, or flashbacks; or intense distress when exposed to reminders of the trauma.
• A marked tendency to avoid people, places, objects, conversations, and other stimuli reminiscent of the trauma (many people who develop ASD after a traffic accident, for example, refuse to drive a car for a period of time).
• Hyperarousal or anxiety, including sleep problems, irritability, inability to concentrate, an unusually intense startle response, hypervigilance, and physical restlessness (pacing the floor, fidgeting, etc.).
• Significantly impaired social functions and/or the inability to do necessary tasks, including seeking help.
• Symptoms last for a minimum of two days and a maximum of four weeks, and occur within four weeks of the traumatic event.
• The symptoms are not caused by a substance (medication or drug of abuse) or by a general medical condition; do not meet the criteria of a brief psychotic disorder ; and do not represent the worsening of a mental disorder that the person had before the traumatic event.

People with ASD may also show symptoms of depression including difficulty enjoying activities that they previously found pleasurable; difficulty in concentrating; and survivor's guilt at having survived an accident or escaping serious injury when others did not. The DSM-IV-TR (revised edition published in 2000) notes that people diagnosed with ASD "often perceive themselves to have greater responsibility for the consequences of the trauma than is warranted," and may feel that they will not live out their normal lifespans. Many symptoms of ASD are also found in patients with PTSD.

Demographics

Acute responses to traumatic stressors are far more widespread in the general United States population than was first thought in 1980, when PTSD was introduced as a diagnostic category in the DSM-III . The National Comorbidity Survey, a major epidemiological study conducted between 1990 and 1992, estimated that the lifetime prevalence among adult Americans is 7.8%, with women (10.4%) twice as likely as men (5%) to be diagnosed with trauma-related stress disorders at some point in their lives. These figures represent only a small proportion of adults who have experienced at least one traumatic event—60.7% of men and 51.2% of women respectively. More than 10% of the men and 6% of the women reported experiencing four or more types of trauma in their lives.

The prevalence of ASD by itself in the general United States population is not known. A few studies of people exposed to traumatic events found rates of ASD between 14% and 33%. Some groups are at greater risk of developing ASD or PTSD, including people living in depressed urban areas or on Native American reservations (23%) and victims of violent crimes (58%).

Diagnosis

ASD symptoms develop within a month after the traumatic event; it is still unknown, however, why some trauma survivors develop symptoms more rapidly than others. Delayed symptoms are often triggered by a situation that resembles the original trauma.

ASD is usually diagnosed by matching the patient's symptoms to the DSM-IV-TR criteria. The patient may also meet the criteria for a major depressive episode or major depressive disorder . A person who has been exposed to a traumatic stressor and has developed symptoms that do not meet the criteria for ASD may be diagnosed as having an adjustment disorder .

As of 2002, there are no diagnostic interviews or questionnaires in widespread use for diagnosing ASD, although screening instruments specific to the disorder are being developed. A group of Australian clinicians has developed a 19-item Acute Stress Disorder Scale, which appears to be effective in diagnosing ASD but frequently makes false-positive predictions of PTSD. The authors of the scale recommend that its use should be followed by a careful clinical evaluation.

Treatments

Therapy for ASD requires the use of several treatment modalities because the disorder affects systems of belief and meaning, interpersonal relationships, and occupational functioning as well as physical well-being.