This has not happened to me. In fact I haven't ever actually been diagnosed with anything although I've been kicking around the mental health services system where I live for over 20 years. I do struggle with a lot of anxiety & always have. And one psychiatrist who saw me said she thought there might be a "bipolar element" to what was going on with me (whatever that means.) However so far as I can discern as a non-professional the misdiagnosis of anxiety for bipolar disorder is unlikely. But that's just my personal impression. Perhaps other PC members may have other thoughts on the subject or other experiences.