How far out of the DSM can you roam before it just gets stupid?

Like I was thinking of a character who had lived through the Time War, and he was supposed to be characterized by dealing with PTSD or something not unlike it. The DSM IV TR says that you need to have experienced trauma and must be constantly reexperiencing it, avoiding situations that remind you of the event combined with a feeling of emotional detachment or numbing, have at least two stress related side effects, and it has to be significantly impairing for at least a month.

So the way I had thought of him was that he was generally fits most of the criteria, except he's not particularly avoidant, and as time goes on he lets less and less numb. And because I have no experience with this, I can't say whether or not this is an unrealistic form for someone with that kind of dysfunction to take. I.E., he doesn't avoid his TARDIS, he doesn't avoid talking about his home world, he does get emotional talking about the war, but not in a way thats described in the text, where it causes distress rather than is just upsetting. However, he does have other pretty typical symptoms, so would it be very odd for him to have some severe reactions but not others? Does a thing like this have to be textbook?

And I guess the main question is that of the subject- how far out of the DSM can you go without it just getting incongruent and ridiculous?

It may be a more narrow focus. As in, talking about the war (in general) or his home world, etc, aren't triggers. However, he may avoid talking about a specific battle or incident. He may avoid the location where it happened. He may also be slowly recovering.

An author can generally stray slightly from the DSM because human variation means that some people will suffer from a problem in atypical ways. I think the key is to KNOW where you are leaving the strict, textbook definition behind, and to do enough additional research to know if you've deviated in entirely the wrong way. Sometimes authors may still get away with that, but they need to lampshade it.

I highly, highly, HIGHLY recommend that you don't use the DSM as your only source. While an excellent starting point, it doesn't provide much meat. I suggest looking for sites (or better, find books) that propose to help individuals who are suffering from this diagnosis. Just keep in mind some of it will be utter and complete crap.

My niece's ex-husband suffers from full-blown PTSD. If you wanna PM me, I know pretty much all the details of what led up to their divorce, and I'd be willing to share things from her POV. Also, as Rae said, you'd do better to read books about actual PTSD sufferers; the DSM IV is a good place to start, but it's pretty cut and dried, and doesn't cover all the nuances of the disease.