The British Psychological Society relesed research that suggests those who are habitual worriers are more likely to develop PTSD following a traumatic event.
The researchers analysed 1000 people from Michigan. Half the participants sufferred a traumatic event during the 10 year study period such as death of a loved one or witnessing a violent incident. Those people that scored high on the neuroticism tests were at a higher risk of developing PTSD.
As the lead researcher stated:
"Pathological worrying is a characteristic common in a wide range of mental health problems, so it's perhaps not surprising that it is now found to be a vulnerability factor for PTSD following traumatic experiences. We know that worrying is an activity that is exacerbated by any factor associated with negative moods such as anxiety and depression, and these are also risk factors for developing PTSD. It will be interesting to see how worrying and it's related characteristics promote PTSD symptoms in vulnerable individuals."
You can read all about the study here.