Defiance, Denial and ADD

Hi. New user with a bunch of questions. I'll start with the main one -- are defiance and denial part of AD/HD?

My wife has ADD and is on meds for it. There are times where she'll voluntarily bring up problems that she has -- managing money, wanting things 'her' way, etc. -- sometimes even joking about it. But when I try to bring these issues up she goes ballistic -- fiercely denying things she admitted to on a different day and trying to change the subject or pin it on me.  I'm extremely careful to not be demeaning or accusatory when I talk to her, but it doesn't matter. She fights me tooth and nail and is often insulting and hurtful.

There are a number of other potential factors -- she has clincal depression (which she's on meds for as well), a terrible relationship with her mother, etc -- but I'm wondering how much of this may be ADD, how much may be another factor and how much may be me (as she often suggests)?

Any personal advice, as well as good articles, books, Web site, etc would be great. Thanks.