Among individuals who have experienced a traumatic event, rates of ASD following the trauma are relatively higher (20 – 50%) for interpersonal traumatic events such as assault or witnessing a mass shooting, relatively lower (13 – 21%) for motor vehicle accidents, and lower still (6 – 12%) for industrial accidents. Because acute stress symptoms often occur in the immediate aftermath of a trauma, a diagnosis should not be made until at least 3 days after the event, and then only when the individual experiences impairment or distress associated with at least nine of the following symptoms (symptoms may be from any or all categories):
- Intrusions, including recurrent, involuntary, distressing memories or dreams related to the traumatic event, flashbacks in which the individual feels or acts like the traumatic event is reoccurring, intense or prolonged emotional distress in response to reminders of the traumatic event, or strong physiological reactions to reminders of the traumatic event.
- Persistent inability to experience positive emotions (e.g., happiness, satisfaction, or love)
- Dissociation, including an altered sense of one’s surroundings (e.g., feeling in a daze or “out of body” in some way), or amnesia for important parts of the traumatic event (not explained by use of substances or head injury sustained during the trauma)
- Avoidance of reminders of the traumatic event, including avoiding distressing thoughts, feelings, or memories related to the traumatic event, or avoidance of external situations (e.g., people; places) that are associated with the traumatic event.
- Changes in autonomic arousal or reactivity following the traumatic event, including irritability or angry outbursts, hypervigilance, exaggerated startle response, impaired concentration, or sleep disturbances (e.g., difficulty falling asleep; disrupted sleep)
Although they do not count toward the diagnosis of ASD, other reactions such as panic attacks, chaotic or impulsive behavior, and guilty ruminations about the causes of the traumatic event are common.