Trauma is defined as a serious injury or shock to the body caused by violence, accidents, or events involving death, injury, or threats that provoke intense fear, helplessness, or horror. Historical trauma refers to the cumulative emotional and psychological effects of massive group trauma experienced across generations. Trauma resides in the nervous system rather than just being a response to the event itself, as the event can strain the body's ability to regulate beyond its capacity, causing the nervous system to disorganize and break down.

1. What is trauma?
A serious injury or shock to the body, as
from violence or an accident.
thefreedictionary.com

2. Experiencing, witnessing, or being
confronted with an event or events
that involved actual or threatened
death or serious injury,
or a threat to the physical integrity of
self or others’
AND
then responding with intense fear,
helplessness, or horror
DSM-IV-TR, American Psychiatric Association, 2001

3. Historical trauma is the “cumulative emotional
and psychological wounding, over the lifespan
and across generations, emanating from
massive group trauma experiences (i.e.
Residential School or the Holocaust)
Historical trauma response is a “constellation
of features” perceived as related, or as a
reaction, to the historical trauma.
Yellow Horse Brave Heart, 2003
Quoted in Rethinking Historical Trauma: Narratives of Resilience,
Aaron R. Denham, 2008

4. Trauma is in the nervous system,
not the event.
Trauma happens when the organism is
strained beyond its adaptational capacity
to regulate…. The (traumatized) nervous
system disorganizes, breaks down
and cannot reset itself.
Peter Levine, founder of Somatic Experiencing Trauma Therapy