There are 4 main types of bipolar disorder:

• Bipolar I Disorder — In this type, you have had at least one episode of mania or mixed mood and often experience depression too. In between, your mood may be normal. Sometimes your mood swings happen when the seasons change.
• Bipolar II Disorder — In this type, you have had at least one episode of depression and at least one period of hypomania. Hypomania is a milder form of mania. In between, your mood may be normal. Sometimes your mood swings happen when the seasons change.
• Cyclothymic Disorder — This is a milder form of bipolar disorder. You may go back and forth between mild depression and a slightly elevated mood. But your mood swings are shorter and less severe. Many people with cyclothymic disorder go on to have a stronger type of bipolar disorder. This doesn’t happen to everyone, though.
• Bipolar Disorder Not Otherwise Specified — This type of bipolar disorder is when you do not fit into the types mentioned above. The feelings of bipolar disorder vary from person to person.

Some people have what is called “rapid-cycling bipolar disorder.” This means they have had 4 or more periods of mania and/or depression in a year.