There are certain conditions that make individuals more susceptible to developing post-traumatic stress disorder. The first one are genetic factors. These are people who tend to be a little bit higher strung than others. A little bit more of an anxious personality, and oftentimes that is inherited. And oftentimes that is environmental. Individuals who are susceptible to abuse when they are children, for instance, or have suffered a previous traumatic brain injury, are more likely to develop post traumatic stress disorder. Then of course, you have to have that incident, that experience that occurs in your lifetime. And so we know that individuals such as soldiers and first responders have many more of those experiences and a prolonged exposure and prolonged exposure is particularly important in developing a longer period, of feeling stress with post-traumatic stress disorder. You can see that in young individuals who we've read about in the news lately, who have been held captive or women who have been held in sex trafficking or actually in sex slavery. So the longer the incident goes on without any help or any support group, the more likely you are to develop PTSD.