Bipolar II Disorder
This type of bipolar disorder is characterized by one or more major depressive episodes with at least one hypomanic episode in which hospitalization is not required. By definition, no actual manic episodes are present in Bipolar II.
Although in some respects Bipolar II is milder than Bipolar I, the condition is still very serious. As with Bipolar I, the rate of completed suicides in patients with Bipolar II Disorder is between 10-15%. The DSM lists school truancy, school failure, occupational failure, and divorce as social problems associated with Bipolar II Disorder. Also of note are other complications such as substance abuse and associated mental disorders such as, Anorexia Nervosa, Bulimia Nervosa, Attention-Deficit/ Hyperactivity Disorder, Panic Disorder, Social Phobia, and Borderline Personality Disorder.
Bipolar II symptoms tend to occur more frequently in women then men. When it does occur in males, the number of hypomanic episodes typically equals that of depressive episodes whereas depression tends to dominate in women. As in Bipolar I Disorder, rapid cycling bipolar disorder is most likely to occur in women. Complications of female biology such as hormones associated with pre-menstruation and postpartum are known to exacerbate already vulnerable moods.
Lifetime prevalence of Bipolar II Disorder is 0.5% in community samples. [DSM]
Cyclothymia is characterized by at least a two-year period characterized by numerous manic or depressive moods, none of which reach the severity necessary for a diagnosis of either full mania or major depression. Instead, hypomanic episodes may be experienced, in conjunction with sub-clinical severity depressive episodes. Individuals with Cyclothymia do not remain symptom-free for more than two months at a time, by definition.
The diagnosis of cyclothymia cannot be made casually. Two full years of documented bipolar symptoms of the proper intensity must have been observed prior to diagnosis. If the mood swings can be better accounted for by the criteria of schizoaffective disorder, then that diagnosis prevails. If mood swings are considered to be a part of a larger schizophrenic disorder, then Cyclothymia becomes an associated feature of a psychotic disorder. If one or more mood episodes reach clinical mood episode proportions, then a diagnosis of Bipolar I or II is appropriate. Additionally, medical conditions such as hypothyroidism must be eliminated as the cause of bipolar symptoms before this diagnosis may be made. Substance abuse may be associated with Cyclothymia, as well as sleep disorders.
Cyclothymic Disorder symptoms often begin early in life and are sometimes considered to reflect a temperamental predisposition to other mood disorders. The condition typically has a slow, gradual, and progressive onset and a chronic course once established. There is a 15-50% chance that cyclothymic individuals will go on to develop bipolar I or II disorders in later life. In community samples, cyclothymic disorder symptoms are apparently equally common in men and in women. As with all bipolar disorders, a general medical condition or substance abuse problem must be excluded in order for this diagnosis to stand.
Lifetime prevalence of Cyclothymia is 0.4% to 1% in community samples. [DSM]
Bipolar Disorder, NOS
This classification is included in the DSM to enable mental health professionals to diagnose disorders with bipolar symptoms that do not meet criteria for any of the defined bipolar disorder subtypes (as described above). For instance, a person who rapidly alternates (over days) between manic and depressive symptoms may be classified under this category. Recurring hypomanic episodes without intervening depression symptoms can lead to this diagnosis as well. A clinician may label a person with bipolar disorder, NOS when he or she suffers from manic or mixed mood episodes that appear to be part of a delusional disorder, residual schizophrenia, or psychotic disorder that is also difficult to classify.
The NOS diagnosis is also sometimes used provisionally, when doctors do not feel they have enough information yet to make a proper bipolar diagnosis, but wish to document their impression that a condition is an instance of bipolar disorder.