In the material below, I've used the terms "Bipolar 1 and 2" and "Bipolar I and II" interchangeably, as different researchers use one or the other of the versions.
The mood swings of Bipolar 2 are not necessarily from low to normal to high and back again. Researchers have found that most patients with Bipolar 2 have more depressive episodes than hypomanic.
Hypomanic EpisodesThe article What Is Hypomania? gives in-depth information about the upper end of the Bipolar 2 mood swings. A few of the most common symptoms are:
- Not needing a lot of sleep, but not being tired
- Having more energy than usual
- Risky behavior, such as reckless spending (see Controlling Spending in Mania and Hypomania for strategies that have helped our readers)
- Grandiosity, pressured speech and/or racing thoughts.
Depressive EpisodesThe article What Is a Major Depressive Episode? gives the specific things a psychiatrist looks for in a patient to gauge the severity of depression. Here are a few of the most common symptoms:
- Insomnia or hypersomnia
- Unexplained or uncontrollable crying
- Severe fatigue
- Loss of interest in things the patient enjoys during euthymia
- Recurring thoughts of death or suicide
Several studies have concluded that Bipolar II is dominated by depression, and also that over time, patients become less likely to return to fully normal functioning between episodes. One study specifically concluded that "bipolar type II is associated with poorer HRQoL [health-related quality of life] compared to type I even during sustained periods of euthymia and excluding residual symptoms."
Thus, researchers have concluded that Bipolar 2 is equally as disabling as Bipolar 1 because they are ill more often, have more lifetime days spent depressed, and don't do as well overall between episodes.
Judd, LL et al. The comparative clinical phenotype and long term longitudinal episode course of bipolar I and II: a clinical spectrum or distinct disorders?. Journal of Affective Disorders. 2003 Jan;73(1-2):19-32.
Mantere, O et al. Differences in outcome of DSM-IV bipolar I and II disorders. Bipolar Disorders. 2008 May;10(3):413-25.
Maina, G et al. Health-related quality of life in euthymic bipolar disorder patients: differences between bipolar I and II subtypes. Journal of Clinical Psychiatry. 2007 Feb;68(2):207-12.
American Psychiatric Association DSM-5 Development. Hypomanic Episode. 2010 May 21.
American Psychiatric Association DSM-5 Development. Major Depressive Episode. 2010 Oct 12.
American Psychiatric Association DSM-5 Development. Bipolar II Disorder. 2011 Jan 24.
Judd, LL et al. A prospective investigation of the natural history of the long-term weekly symptomatic status of bipolar II disorder. Archives of General Psychiatry. 2003 Mar;60(3):261-9.
Swartz, HA, and Thase, ME. Pharmacotherapy for the Treatment of Acute Bipolar II Depression: Current Evidence. Journal of Clinical Psychiatry. 2011;72(3):356-366.