Can a person have bipolar without mania?

Unclear: By strict definition, a diagnosis of bipolar disorder can only be made if their is a history of mania. Many individual have subtle hypomanic symptoms that can only be discovered by a physician experienced in bipolar disorder who gets an extensive history from the patient and someone close to them. However, I have seen patients that I have diagnosed with bipolar depression that i can't find mania.

Yes and no: Technically, depression alone would be unipolar depression. Mania is the most severe form of an elevated mood. Bipolar 2 is often mainly depression and very subtle hypomanic symptoms may not be recognized. Bipolar is a disorder of affect which means your mood and overall perspective. Self esteem is a key element, but my main criterion for hypo/mania is a decreased need for sleep.