Kay Ray asked:
What can feasibly be done to prevent post traumatic stress, i.e. do we know enough about the brain processes involved to inoculate or intervene? How can the military use neuroscience to screen and allocate personnel?
Amy - People who do go on to develop posttraumatic stress have some difference in their brains compared to those who don’t develop PTSD. So for example, they tend to have a smaller hippocampus. Now, that's the structure that allows the memory to have a distinct time and place. So, that may mean that that trauma memory is not localised to a point in someone’s past in a specific space and time, but that fear then becomes generalised to all situations and it persists in a way that it doesn’t to people who don’t develop PTSD.
We also know that areas like the amygdale, that's an area that's really important for storing the effective value of environmental cues. So, that would include fearful stimuli in the environment, fearful things and there also seems to be some differences in the ability of the prefrontal cortex which is an area that normally regulates all of these emotional processing.
There appear to be some difference in those who develop posttraumatic stress as well.
The difficulty is that the bulk of this work is being done in human patients using structural brain imaging studies. But all of these of course happens post trauma. So, whether these differences existed before somebody was exposed to the traumatic event or whether they've developed afterwards is really difficult to disentangle.
And what we don’t have is a sort of a long term screening study for example in a rodent model where you can actually try to tease apart this correlation and know which way the causality runs.
Hannah - So, in that case, we can't really – as Kay asks, we can't neuroscience to screen and find out whether certain people might be more predisposed to experiencing posttraumatic stress disorder later on in life and therefore, shouldn’t maybe be at the front line
Amy - We’re not in a position where we can do that on an individual basis yet. So, we have risk factors, but they're very, very statistical. So for example, women are more likely to develop posttraumatic stress than men are, but that doesn’t necessarily mean that we shouldn’t let women into the army. You can make the same argument that men are more likely to become addicted to alcohol than women. Therefore, we shouldn’t allow men into pubs. So, it’s all very broad brush at the moment and there's no diagnostic screen. You couldn’t scan someone’s brain and say, “Based on this volume of these, how big these brain structures are, they shouldn’t go on the front line.” So, we can't do that yet.