It's defined as any persistent psychological difficulty. Originally the context was deployment to a mission, but it has been broadened to service in the Canadian Forces. It could be related to an accident you had while training in Wainwright on your way there. That's just as much of an issue.
It can manifest itself as depression, anxiety, phobias, or post-traumatic stress disorder and—this is almost anathema to put in the room—the worsening of a personality disorder. Somebody might have had certain traits in their personality that made them a little hard to get along with, and then under stress it can push them over the threshold into a personality disorder. Substance use or any combination of all of that....