It's an interesting topic.

I have had several different pdocs talk about completely different ideas as to what comprises "Atypical Depression," when it was noted in my medical records. I believe it is a term that has become over-used and no longer indicates any specific condition, but many different conditions.

At this university, when someone's diagnosis is noted as "atypical," the question is : What did the prior pdoc mean? Atypical in what way?

I am told by my friend who is a professor of psychiatry here at the medical university: What used to be called "atypical" depressions used to be very severe and are now more commonly now known as "Bipolar Depression."

From what I have read and have been told by practitioners (pdocs), the rapid changes in mood, as in changes within any given day, are characteristic of BPD.

So many different sources have different ideas/info in this topic.