How do you know that you might have bipolar disorder?

Bipolar. Bipolar I and bipolar II, In the first, manic phases are more severe, and in the second, depressive phases are more severe. There is also cyclothymia which is a low grade version of bipolar disorder in general, where mood swings are not as severe in either direction, manic or depressive. A psychiatrist will look for extreme swings of mood as part of formulating a diagnosis as opposed to testing.
Mood Swings. Such patients have intermittent episodes of mania, an agitation psychotic state, the so called " high" and depression, the "low", when they are quite the opposite. Such highs and lows are the main characteristic of this disorder although there are severe accompanying symptoms to further classify the disorder in various stages.