I don't know about PTSD for those under 12 years specifically. However, the DSM-5 has different criteria for PTSD for those who are under age 6. Here it is:1. In children 6 years and younger, exposure to actual or threatened death, serious injury, or sexual violence in one (or more) of the following ways:
Directly experiencing the traumatic event(s). Witnessing, in person, the event(s) as it occurred to others, especially primary caregivers. Learning that the traumatic event(s) occurred to a parent or caregiving figure.
2. Presence of one (or more) of the following intrusion symptoms associated with the traumatic event(s), beginning after the traumatic event(s) occurred:
Recurrent, involuntary, and intrusive distressing memories of the traumatic event(s). Recurrent distressing dreams in which the content and/or affect of the dream are related to the traumatic event(s). Dissociative reactions (e.g., flashbacks) in which the child feels or acts as if the traumatic event(s)
were recurring. Such trauma-specific reenactment may occur in play.
Intense or prolonged psychological distress at exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event(s). Marked physiological reactions to reminders of the traumatic event(s).
3. One (or more) of the following symptoms, representing either persistent avoidance of stimuli associated with the traumatic event(s) or negative alterations in cognitions and mood associated with the traumatic event(s), must be present, beginning after the event(s) or worsening after the event(s): Persistent Avoidance of Stimuli Avoidance of or efforts to avoid activities, places, or physical reminders that arouse recollections of the traumatic event(s).
Avoidance of or efforts to avoid people, conversations, or interpersonal situations that arouse recollections of the traumatic event(s). Negative Alterations in Cognitions Substantially increased frequency of negative emotional states (e.g., fear, guilt, sadness, shame, confusion). Markedly diminished interest or participation in significant activities, including constriction of play. Socially withdrawn behavior. Persistent reduction in expression of positive emotions.
4. Alterations in arousal and reactivity associated with the traumatic event(s), beginning or worsening after the traumatic event(s) occurred, as evidenced by two (or more) of the following: Irritable behavior and angry outbursts (with little or no provocation) typically expressed as verbal or physical aggression toward people or objects (including extreme temper tantrums). Hypervigilance. Exaggerated startle response. Problems with concentration. Sleep disturbance (e.g., difficulty falling or staying asleep or restless sleep).
5. The duration of the disturbance is more than 1 month.
6. The disturbance causes clinically significant distress or impairment in relationships with parents, siblings, peers, or other caregivers or with school behavior.
7. The disturbance is not attributable to the physiological effects of a substance (e.g., medication or alcohol) or another medical condition.
Some other PTSD symptoms in children might be: being difficult to soothe, becoming clingy, feeling helpless and developing eating disorders.
I don't know about PTSD for those under 12 years specifically. However, the DSM-5 has different criteria for PTSD for those who are under age 6. Here it is: 1. In children 6 years and younger, exposure to actual or threatened death, serious injury, or sexual violence in one (or more) of the following ways:
Directly experiencing the traumatic event(s). Witnessing, in person, the event(s) as it occurred to others, especially primary caregivers. Learning that the traumatic event(s) occurred to a parent or caregiving figure.
2. Presence of one (or more) of the following intrusion symptoms associated with the traumatic event(s), beginning after the traumatic event(s) occurred:
Recurrent, involuntary, and intrusive distressing memories of the traumatic event(s). Recurrent distressing dreams in which the content and/or affect of the dream are related to the traumatic event(s). Dissociative reactions (e.g., flashbacks) in which the child feels or acts as if the traumatic event(s)
were recurring. Such trauma-specific reenactment may occur in play.
Intense or prolonged psychological distress at exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event(s). Marked physiological reactions to reminders of the traumatic event(s).
3. One (or more) of the following symptoms, representing either persistent avoidance of stimuli associated with the traumatic event(s) or negative alterations in cognitions and mood associated with the traumatic event(s), must be present, beginning after the event(s) or worsening after the event(s): Persistent Avoidance of Stimuli Avoidance of or efforts to avoid activities, places, or physical reminders that arouse recollections of the traumatic event(s).
Avoidance of or efforts to avoid people, conversations, or interpersonal situations that arouse recollections of the traumatic event(s). Negative Alterations in Cognitions Substantially increased frequency of negative emotional states (e.g., fear, guilt, sadness, shame, confusion). Markedly diminished interest or participation in significant activities, including constriction of play. Socially withdrawn behavior. Persistent reduction in expression of positive emotions.
4. Alterations in arousal and reactivity associated with the traumatic event(s), beginning or worsening after the traumatic event(s) occurred, as evidenced by two (or more) of the following: Irritable behavior and angry outbursts (with little or no provocation) typically expressed as verbal or physical aggression toward people or objects (including extreme temper tantrums). Hypervigilance. Exaggerated startle response. Problems with concentration. Sleep disturbance (e.g., difficulty falling or staying asleep or restless sleep).
5. The duration of the disturbance is more than 1 month.
6. The disturbance causes clinically significant distress or impairment in relationships with parents, siblings, peers, or other caregivers or with school behavior.
7. The disturbance is not attributable to the physiological effects of a substance (e.g., medication or alcohol) or another medical condition.