The following article found that terrible memories become harder to ignore after sleeping. This suggests that sleeping ‘consolidates’ the memory. Thus insomnia, which is an often symptom in stressed individuals, protect against PTSD or bad memories. Very interesting study.
Another hypothesis I have is that recalling and talking about bad memories heightens the chance of getting PTSD or depression. It also consolidates the memory.
Consolidating efforts heighten the chance of developing emotionel distress later on.
A writing place. 