I was diagnosed major depression then postpartum depression then bipolar II ,then bipolar I after I had a giant manic episode in the pdoc's waiting room & office on a scheduled appt. day. Narrowly missed the hospital on that one and would have been in there if not for H.

Not much difference in how they treat the 2, though I have noticed since the BP1 diagnosis, I get quick responses and med adjustments or appts. if I call regarding lack of sleep or hypomania. I get help for the hypo, even if it feels good because I quickly become fully manic, and it's bad.

I think BP1 might be more likely to become mixed, not sure about that one though I have now been mixed for ages, and that sucks.

It's not so much the diagnosis really. The treatment is mostly the same, and it depends if you have other mental illnesses too. Like I'm half the walkding DSM-V, I feel like as well as a pharmacy. Sigh.

I would have been different if diagnosed sooner, but in my case, with a major depression diagnosis, I was on SSRIs for 10 years, which would cause me mania, and I'd be ashamed to admit what I did while manic to the pdoc. I didn't realize it was mania anyway. If the first pdoc had asked all the questions in the right way, everything was there, he could have diagnosed bipolar and didn't, and so many later pdocs did not choose to re-diagnose, just accepted the major depression diagnosis. For me, yeah, the wrong diagnosis hurt a lot, but is is not like I can go back & undo it and have a re-do of all those years. Wouldn't be surprised if wrong meds caused brain changes that were worse than they would have been otherwise. But who knows?