Such a great question! Anxiety can be an element of depression, mania, psychosis, or mixed episodes. It is the most common secondary "diagnosis" or symptom complex outside DSM 9000 criteria--third is phobias, esp agoraphobia.

The extent to which a given pdoc wishes to add an official additional label of GAD, say, is likely largely due to their training and practice style, in my experience. I never got an additional dx, despite panic attacks requiring klonopin and phobias. Most of my pdocs have just felt this was all bp-related.

Hugs!