Bipolar Types

One of my new patients introduced herself this way, “Hello Dr. Forster, I have Bipolar 2 and a half.”

Had she just finished watching Harry Potter and was thinking about the invisible platform that takes young wizards to Hogwarts?

No, she was referring to a type system developed by Hajop Akiskal, probably one of the most influential thinkers in the field of mood disorders.

Many of us know about Bipolar 1 and Bipolar 2, but what is Bipolar 2 and a half?

Akiskal Bipolar Types

This term comes from a list of the types of bipolar identified by Dr. Akiskal in his article in Psychiatric Clinics of North America in 1999:

  • Bipolar 1 – This is the “typical” bipolar of manic episodes (energized periods that are associated with significant impairment and may even require hospitalization) and depressive episodes. It is worth noting that, even for bipolar 1 patients, mania is much less common than depression…
  • Bipolar 2 – These are people with periods of depression that are often quite severe who have brief periods of being mildly energized. The mild energized periods are called hypo (a little) mania and are often viewed as desirable or even normal mood states.
  • Bipolar 2½ – This refers to people who have had ongoing mild mood cycles (called “cyclothymia) for years who then develop a major depression. In DSM these would often be diagnosed with both bipolar 2 and cyclothymia. Bipolar Types Akiskal Part 2
  • Bipolar 3 – This refers to someone who develops a hypomanic episode only in the context of treatment with an antidepressant. It is a controversial diagnosis and Akiskal thought (and his studies suggested) that most of these people go on to develop some form of bipolar when not taking antidepressants.
  • Bipolar 4 – Refers to people who have what Akiskal called the “hyperthymic temperament” – they are always filled with an unusual amount of energy –  who develop (often later in life) a tendency to have major depressions, but who have not had these episodes for most of their lives. The book “The Hypomanic Edge” may actually be describing hyperthymic temperament in some cases. Very successful entrepreneurs who experience depression for the first time in middle age.
  • Depressive Mixed State – The “mixed state” – which is a period of being energized (talking rapidly, perhaps making impulsive decisions) associated with a profound dysphoria or negative mood – is one that Akiskal pointed out was much more common than the “typical” euphoric manic state. Distinguishing this from “agitated depression” can be difficult…
  • Recurrent “Unipolar” – Akiskal felt that certain people, who have never had manias or hypomanias, but otherwise have cycled in the same way as bipolar patients, could be thought to have a form of bipolar. This is a controversial idea but it has a long history, dating back to the founder of modern “nosology” (psychiatric diagnosis) Emil Kraepelin in 1899.


Akiskal HS, Pinto O. Psychiatr Clin North Am 1999;22:517­34.