Table 1. DSM-5 Diagnostic Criteria for PTSD.

Criterion 1: Exposure to a traumatic event • Directly experiencing the traumatic event(s) • Witnessing, in person, the event(s) as it occurred to others • Learning that the traumatic event(s) occurred to a close family member or friend • Experiencing repeated or extreme exposure to aversive details of the traumatic event(s); this does not apply to exposure through media such as television, movies or pictures

Criterion 2: Persistent re-experiencing of the event in one of several ways: • Thoughts or perception • Images • Dreams • Illusions or hallucinations • Dissociative flashback episodes • Intense psychological distress or reactivity to cues that symbolize some aspect of the event

Criterion 3: Avoidance of stimuli associated with the trauma and numbing of general responsiveness, as determined by the presence of one or both of the following: • Avoidance of thoughts, feelings or conversations associated with the event • Avoidance of people, places or activities that may trigger recollections of the event

Criterion 4: At least two symptoms of negative alterations in cognitions and mood associated with the trauma: • Inability to remember an important aspect of the event(s) • Persistent and exaggerated negative beliefs about oneself, others or the world • Persistent, distorted cognitions about the cause or consequences of the event(s) • Persistent negative emotional state • Markedly diminished interest or participation in significant activities • Feelings of detachment or estrangement from others • Persistent inability to experience positive emotions

Criterion 5: Marked alterations in arousal and reactivity, as evidenced by at least two of the following: • Irritable behaviour and angry outbursts • Reckless or self-destructive behaviour • Hypervigilance • Exaggerated startle response • Concentration problems • Sleep disturbance

Criterion 6: The duration of symptoms is more than 1 month

Criterion 7: The disturbance causes clinically significant distress or impairment in functioning

Criterion 8: The disturbance is not attributable to the physiological effects of a substance or other medical condition

Note: Unlike adults, children re-experience the event through repetitive play rather than through perception.