My T uses severe depression as my diagnostic code for insurance. He has a great deal of diagnostic training and experience, so he also says ptsd and bipolar but mainly as a point of reference, not officially on paperwork for insurance. His assessment is the same as my pdoc, but my pdoc actually uses bipolar as my diagnostic code. Insurance doesn't seem to care that there is a difference.

I'd say for the most part the diagnoses are a point of reference for treatment and monitoring.