[yossarian]

Here's the thing about diagnosing people... isn't it sort of impossible without their cooperation?

I mean when you don't have their active co-operation and their sincere responses to probing questions, how can it really mean anything?

And then of course-

"It is no measure of health to be sane in an insane world."

There is nothing necessarily wrong with fitting the criteria of a mental disorder. The big question is whether it is maladaptive in the person's life - and this depends on subjectivity - ultimately coming down the patient's own hopes and desires.