Dear Sharla,
I'm not exactly sure what is a mixed state either.
But I know I experienced them for years and they were awful.
Essentially in my case they were moods combined with the energy of mania and the low low part of depression --- basically the worst of both at the same time.
http://www.psycheducation.org/depres...diagnosis.html
Also
http://www.psycheducation.org/depression/Waves.htm
M.