ADHD and Depression are extremely common misdiagnosis for bipolar, either by themsevles or together. It's almost not fair to say it's a misdiagnosis rather than a piece of the puzzle considering that the definition of bipolar includes periods of depression and symptoms much like ADHD. Bipolar symptoms can also mirror other disorders like anxiety disorders and ADHD, though it's also possible to say that these disorders are comorbid.

In fact, bipolar symptoms over lap so often with other disorders that it can take years (apparently averaging 10 for BP2) for the patient to receive a correct diagnosis. Crazy.

Antidepressants are generally considered rather toxic for people diagnosed with bipolar because it can spurn their cycling, destabilize them, and send them into mania. However, many BP folk who lie predominantly in depression often benefit from a mood stabilizer along with an AD. I have heard that a 'soft' sign of bipolar is failed trails of antidepressants or frequent 'poop-out', as in an AD can work for a matter of weeks, months, maybe a year before it stops working like the rest.