I was diagnosed when I was 28. I went to several pdocs after that initial diagnosis and none questioned it.

When I was 35 I moved back to my home state. My new pdoc told me that bp is overdiagnosed (which I totally believe) and he didn't think I had it (I present myself fairly well). Queue manic episode about 2 months later and new pdoc told me there was no question that I was bp1.

I've been with him 10 years now and he has never wavered in the diagnosis.