By: Rachael Rettner 
Published: 07/09/2013 02:03 PM EDT on LiveScience

People with post-traumatic stress disorder (PTSD) often show differences in certain brain areas compared to healthy people, but it's been difficult for researchers to determine whether these differences are a cause or a consequence of the condition.
Now, a number of new studies may help researchers disentangle the condition's causes from its effects and, in doing so, bring a better understanding of how the disorder might be prevented or treated.
In a new review article, researchers draw upon these studies to piece together a new model for how the condition arises.
The model suggests that three factors are necessary in order for PTSD to develop: a person needs to have certain risk factors for the condition, he or she must be exposed to a traumatic event, and after that event, further changes to the brain need to occur.
Read the full story at Huffington Post