How people deal with loss differs for everyone. There isn't one right way to deal with it. How much it impact a person...well, that depends on a lot of things. The nature of the loss, when it happens, how close you were to who was lost...
As for PTSD, I'm afraid I only know the textbook medical definitions. [He's a medic, not a therapist]
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As for PTSD, I'm afraid I only know the textbook medical definitions. [He's a medic, not a therapist]