Yes, there are types of bipolar disorder where a person may primarily experience one pole of the illness (either depression or mania/hypomania) and rarely or never experience the other pole. These variations are known as "bipolar spectrum disorders" or "bipolar disorder subtypes."
Bipolar II Disorder: In Bipolar II Disorder, individuals experience recurrent depressive episodes, which are similar to major depressive disorder (unipolar depression). However, instead of full-blown manic episodes, they experience hypomanic episodes. Hypomania is a milder form of mania, characterized by elevated mood, increased energy, and other symptoms of mania, but the symptoms are less severe and do not cause significant impairment. People with Bipolar II Disorder do not experience full manic episodes.
Cyclothymic Disorder: Cyclothymic Disorder is a milder form of bipolar disorder characterized by chronic mood fluctuations. People with cyclothymia experience numerous periods of mild depression and hypomania, but the symptoms do not meet the criteria for major depression or full hypomania.
Bipolar Spectrum: Some researchers and clinicians propose that bipolar disorder should be conceptualized as a spectrum, where individuals may fall at various points along the spectrum with different combinations of depressive and manic/hypomanic symptoms. This spectrum includes cases where individuals may experience depression without classic hypomanic or manic episodes, or vice versa, experiencing hypomania or mania without experiencing significant depressive episodes.
In all these cases, it's important to recognize that while the person may not experience full-blown mania, hypomania, or depression, they still have a distinct pattern of mood fluctuations that differ from the typical ups and downs of daily life.
Diagnosing bipolar disorder subtypes can be challenging because it requires careful observation of mood patterns over time. If you or someone you know is experiencing mood disturbances or other mental health symptoms, it's crucial to seek professional help for an accurate diagnosis and appropriate treatment. Bipolar disorders, including their milder forms, can be effectively managed with the right treatment and support.