This ailment is characterized by mood swings, someone who is very happy one moment may go into unhappy state within a short period of time. Bipolar depression is also known as mania depression.
There are four sub-categories of bipolar depression. They are:
Ø Cyclothymic Disorder
Ø Bipolar NOS
Ø Bipolar I Disorder
Ø Bipolar II Disorder
This is a milder but much more long-term version of bipolar disorder (usually lasting for two or more years).
Like bipolar II the mania phases are relatively minor, but in addition their depressive phases aren't so severe that they classify as major depression. If left untreated, cyclothymic depression can develop into bipolar II depression.
Bipolar NOS (Not Otherwise Specified) is a catch-all category for people who have some of the symptoms of bipolar, but those symptoms don't allow the person to be neatly categorized in one of the three other categories. For example, the sufferer may have fast cycling between the manic and depressive states, or manic states without depressive states.
Bipolar I Disorder
People suffering from bipolar I disorder have the most extreme mood swings. Their low moods can be classified as major depression, while in their positive moods they can engage in crazy, outrageous and dangerous activities. During this mania state they may even suffer from paranoia or hallucinations.
Bipoar II Disorder
People with bipolar II disorder have much less extreme mania periods. Indeed, many bipolar II sufferers go untreated because people mistake their 'mania' phase for simply getting over their depression. People with bipolar II don't suffer from paranoia or hallucinations.