It's a beautiful thing for humans to have social connection and communication skills. The ability to communicate and interpret voices, sounds and body movement in a way that conveys a certain feeling or reaction is greatly remarkable!
There have been decades of studies and research and much information has been uncovered by the evidence behind traumatic events. One thing that is certain is that many people who go through traumatic events fail to process or interpret the situation properly. The brain also has a "mind of it's own" and can remove certain memories and even confuse a person by changing up the sequence of events for a traumatic situation This can result in a change of the hippocampus. Any physical changes in the hippocampus can result in diminished ability to perceive or even recover for certain stress factors.
Thankfully there has been a therapy developed by Jon Connelly."He uses a strong interpersonal connection built from the first moments of the session and builds a model for calm, centered, enlightened functioning with the client."