Bipolar I
Bipolar I is manic-depression at its dubious best. If you get a diagnosis of bipolar I disorder, you've experienced at least one full-blown manic episode-- and likely at least one major depression as well. Although it's true that in nearly three-quarters of bipolar I cases, mania and depression will switch off in a somewhat orderly progression, there's really no rhyme or reason to the episodes: Depression might lead to mania, or mania to depression. They can be mixed in a single week or day or they can be seperated by months or even years.

Bipolar I is the most severe form of bipolar disorder. If you have bipolar I and don't treate it, you're likely to experience as many as four mood episodes a year. Untreated manias might last for a month or more -- an eternity spent in a world of frenzy. Untreated depressions can linger for months and months on end; some can even last for a year or more.

If your clinician diagnoses you with bipolar I, he or she will usually add a variety of modifiers such as delusions and hallucinations. If you're a woman, your doctor might also consider whether your symptoms were kicked off or restarted by giving birth.

Bipolar I affects more than 2 million people in the United States, or about 1 percent of the population. Despite the fact that it is the best-known and most easily recognized form of the disorder, it is not the most common forum. That particular dupious honor is reserved for bipolar II disorder.


Bipolar II
If you're bipolar II, you've never been out-and-out manic, but instead you have gone through at least one or more hypomanias (you don't go as "high" as full-blown mania) as well as at least one major depression.

It's tempting to talk about bipolar II as "less severe" than bipolar I. Cerainly, the symptoms of mania are less striking than they are in bipolar I, and if you're bipolar II, you're more likely to return to "normal" between hypomanic and depressive episodes. In fact, in a long-term study of bipolar Ii patients led by Lewis Judd, M.D., of the University of California, San Diego, the authors noted that although bipolar II patients spend a lot of their time with symptoms of depression, more often than not, those symptoms are relatively mild compared to those needed for a diagnosis of a major depressive episode.

But bipolar II has its own special brand of treachery. Those normal periods of time? They're shorter than in bipolar I. You're more likely to keep having episodes over time -- bipolar II has a more chronic course than bipolar I. You're also more likely to experinece rapid cycling. And because of the amount of time you spend depressed, if you have a diagnosis of bipolar II, you're more likely to commit suicide than someone who is bipolar I. this is a particularly devastating issue, because bipolar II disorder is two to three times more common than bipolar I.

"To paraphrase Kraepelin," wrote Judd and his collegues in their 2003 Archives of General Psychitary paper, "the nature of this deceptively 'milder' form of manic depressive illness is so chronic as to seem to fill the entire life."