I'd like to add a little bit to that answer. Prior to this, everyone had post-traumatic stress disorder, and they never even made the diagnosis based on an appropriate standard diagnosis. So a lot of times there was a written diagnosis, but in fact it did not meet the criteria that were set.
So in order to add rigour to this, they basically said that first of all they wanted to standardize the criteria. When you say that someone is suffering from post-traumatic stress disorder, let's make sure they meet all the criteria of that, so if we're talking about oranges, we all understand what oranges means. Then there are other symptoms that go along with that diagnosis.
Trying to put some definition to that was the job of the mental health services, and they did an excellent job by coming together, deciding how they were going to work together, deciding what the criteria were, and trying to define those. In the past there was very little rigour applied to how diagnoses were made, etc.