What is bipolar disorder?

Manic depression: Psychiatric condition where subject experiences both episodes of severe depression & mania or hypomania. These episodes are frequently cyclical or seasonal. Subject often attributes depressive episodes to external causes such as unpleasant boss or feeling ill. Manic episodes can vary from being"life & soul of the party" to being extremely obnoxious & "impossible". Best treated by a psychiatrist.

Major Mental Illness: Bipolar disorder is a lifelong mental illness which features recurrent episodes of severe depression and of hypomania/mania - which is best explained as the opposite of depression. Bipolar disorder usually has a strong biological basis. The diagnosis is best made by a psychiatrist. The phrase, "he/she is bipolar" used by lay people often implies emotionality, not the diagnosis.

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.