Like other mental illnesses, bipolar disorder cannot yet be identified physiologically for example, through a blood test or a brain scan. Therefore, a diagnosis of bipolar disorder is made on the basis of symptoms, course of illness, and, when available, family history. The diagnostic criteria for bipolar disorder are described in the Diagnostic and Statistical Manual for Mental Disorders, fourth edition (DSM-IV).

Descriptions offered by people with bipolar disorder give valuable insights into the various mood states associated with the illness:

Depression: I doubt completely my ability to do anything well. It seems as though my mind has slowed down and burned out to the point of being virtually useless. [I am] haunt[ed] with the total, the desperate hopelessness of it all. Others say, “It’s only temporary, it will pass, you will get over it,” but of course they haven’t any idea of how I feel, although they are certain they do. If I can’t feel, move, think or care, then what on earth is the point?

Hypomania: At first when I’m high, it’s tremendous ideas are fast like shooting stars you follow until brighter ones appear. All shyness disappears, the right words and gestures are suddenly there uninteresting people, things become intensely interesting. Sensuality is pervasive, the desire to seduce and be seduced is irresistible. Your marrow is infused with unbelievable feelings of ease, power, well-being, omnipotence, euphoria you can do anything but, somewhere this changes.

Mania: The fast ideas become too fast and there are far too many overwhelming confusion replaces clarity you stop keeping up with itmemory goes. Infectious humor ceases to amuse. Your friends become frightened. everything is now against the grain you are irritable, angry, frightened, uncontrollable, and trapped.