My W has mentioned recently that she would like to see a psych. The teacher she works for thinks it will do her a lot of good. I sent W a link to the web site for the author that wrote the "Walk out woman" book who practices nearby. My mother has even mentioned that my W should be checked to see if she is bi-polar.
Great first step - Make sure she sees both a psych and a C. It may be helpful if you can get the two to share information so they can help her more. I'm sure there is a load of stuff going on behind the scenes that you don't know about and she has no clue how to deal with... Maybe like my W it's really old stuff that just built up over time.