Criterion A. Exposure to actual or threatened death, serious injury, or sexual violence in at least 1 of the following ways:

1. Directly experiencing the traumatic event(s).
2. Witnessing, in person, the event(s) as it occurred to others.
3. Learning that the traumatic event(s) occurred to a close family member or close friend. In cases of actual or threatened death of a family member or friend, the event(s) must have been violent or accidental.
4. Experiencing repeated or extreme exposure to aversive details of the traumatic event(s) (e.g., first responders collecting human remains: police officers repeatedly exposed to details of child abuse).

Note: Criterion A4 does not apply to exposure through electronic media, television, movies, or pictures, unless this exposure is work related.

Criterion B. Presence of at least 9 of the following symptoms from any of the five categories of (1) intrusion, (2) negative mood, (3) dissociation, (4) avoidance, and (5) arousal, beginning or worsening after the traumatic event(s) occurred:

Intrusion Symptoms

1. Recurrent, involuntary, and intrusive distressing memories of the traumatic event(s). In children older than 6 years, repetitive play may occur in which themes or aspects of the traumatic event(s) are expressed.
2. Recurrent distressing dreams in which the content and/or affect of the dream are related to the traumatic event(s). In children, there may be frightening dreams without recognizable content.
3. Dissociative reactions (flashbacks) in which the individual feels or acts as if the traumatic event(s) were recurring. (Such reactions may occur on a continuum, with the most extreme expression being a complete loss of awareness of present surroundings.) In children, trauma-specific reenactment may occur in play.
4. Intense or prolonged psychological distress at exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event(s)

Negative Mood

1. Persistent inability to experience positive emotions (e.g. inability to experience happiness, satisfaction, or loving feelings)

Avoidance Symptoms

1. Efforts to avoid distressing memories, thoughts, or feelings about or closely associated with the traumatic event(s)
2. Efforts to avoid external reminders (people, places, conversations, activities, objects, situations) that arouse distressing memories, thoughts, or feelings about or closely associated with the traumatic event(s)

Arousal Symptoms

1. Sleep disturbance (e.g., difficulty falling or staying asleep, restless sleep)
2. Irritable behaviour and angry outbursts (with little or no provocation), typically expressed as verbal or physical aggression toward people or objects
3. Hypervigilance
4. Problems with concentration
5. Exaggerated startle response

Dissociative Symptoms

1. An altered sense of the reality of one’s surroundings or oneself (e.g. seeing oneself from another’s perspective, being in a daze, time slowing)
2. Inability to remember an important aspect of the traumatic event(s) (typically due to dissociative amnesia and not to other factors such as head injury, alcohol, or drugs)

Criterion C. Duration of the disturbance (symptoms in Criterion B) is 3 days to 1 month after trauma exposure.

Note: Symptoms typically begin immediately after the trauma, but persistence for at least 3 days and up to a month is needed to meet disorder criteria.

Criterion D. The disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.

Criterion E. The disturbance is not attributable to the physiological effects of a substance (e.g. medication or alcohol) or another medical condition (e.g. mild traumatic brain injury) and is not better explained by brief psychotic disorder.