Bipolar disorder affects about 2% of the people over the age of 18 in the United States: that equals more than five million people. In general, most people begin showing signs of the disorder at around 25 years of age, although it can appear in younger people as well. Bipolar 1 and Bipolar 2 are just two types of the disorder, but they are the two most severe.
A Bipolar 1 diagnosis does not require a history of any depressive episode (symptoms similar to clinical depression). A Bipolar 2 diagnosis requires at least one depressive episode in the life of the patient.
To be diagnosed with Bipolar 1, you need to have had at least one full-blown manic episode, including symptoms of increased energy, outgoingness and eventually paranoia. People who have Bipolar 2 do not have full manic episodes. Instead, they have hypomanic episodes that lack hallucinations and paranoia.
A mixed episode includes symptoms from both manic and depressive episodes. Bipolar 1 patients can have these episodes; Bipolar 2 patients do not have mixed episodes.
People who have Bipolar 1 usually have only one manic or depressive episode per year if the condition is left untreated. People who have Bipolar 2 can have up to four episodes annually, on average.
One similarity is the risk of attempting suicide. One-fourth of people who have some type of bipolar disorder that is not being treated will attempt suicide at some point in their lives. About 15% of patients are successful.