Bipolar disordersYao- qian kunBipolar disorder is a prevalent, disabling, and recurrent psychiatric disease, which until recently was equated with classic manic depressive illness (i.e. bipolar disorder). Major depressive disorder and bipolar disorder constitute the two major mood disorders in psychiatry.However, bipolar disorder encompasses a much broader range of illnesses than bipolardisorder. This range of illnesses is often refered to as bipolar spectrum disorders and include bipolar disorder, bipolar disorder ,and other forms of bipolar disorder. In general, bipolar disorder is characterized by a dysregulation of mood and associated risky behavior, impulsivity, and interpersonal problems. Bipolar disorder causes significant impairment in social, occupational, or other important areas of functioning, and may lead to premature mortality through suicide. WHO identified bipolar disorder as the sixth leading cause of disability-adjusted life years (DALY s) in the world among people aged 15-44 years.To sum up, bipolar disorder is a chronic mood disorder that places a significant burden not only on the patients, but also on their families and society in general.EpidemiologyThe lifetime prevalence rate of bipolar disorder is about 1 percent in western countries, and this is true across almost all social classes, education levels and races.According to WMH-CIDI (World Mental Health- Composite International Diagnostic Interview) surveys, in East Asia and Pacific regions the lifetime prevalence rate of bipolar disorder is 0.1%-0.7%.In Korea, a nation-wide epidemiological study conducted in 2001 showed that the lifetime prevalence rate of this mental illness was 0.4% and, in terms of the number of DALYs caused by neuropsychaitric disorders, bipolar disorder was ranked 5th.However, if the diagnosis of bipolar disorder and other subtypes (mixed or depressed) is included in this calculation, much higher prevalence rates of approximately 5 percent are obtained.In contrast to unipolar depression, the gender ratio in bipolar is approximately1:1.However, when the depression-mania continuum is considered as a spectrum of mood disorders, a distinct trend is observed, namely that the higher the depressive component, the higher proportion of women. Current evidence indicates that the peak age of onset is situated between late adolescence and early adulthood that is around 20 years of age.Onset after age 60 is rare. Like major depressive disorder, bipolar illness is more prevalent among divorced, separated, or widowed individuals. From the genetic point of view, bipolar illness has a higher heritability than unipolar affective disorder. The concordance rate for bipolar illness in monozygotic twins is reported to be as much as 79%; in dizygotic twins the rate is approximately 24% in primarily European and U.S population.Symptoms and SignsManic episodesThe essential criterion for diagnosis of bipolar disorder is a past or present history of one or more manic episodes. Manic episodes are defines as a distinct period during which there is an abnormally and persistently elevated, expansive, or irritable mood. This period of abnormal mood must last for at least 1 week. In many manic episodes, and particularly in the initial stages, the predominant mood is euphoria. The euphoria experienced by the manic patient has an infectious quality. The expansive quality of the mood is characterized by unceasing and indiscriminate enthusiasm for interpersonal, sexual, or occupational interactions. Although elevated mood constitutes the core symptom of manic episodes, the predominant mood disturbance may also frequently observed, and the subjects mood is often accompanied by a sense of conviction usually involving a self-perceived talent or perception and occasionally resulting in a marked sense of a manic grandiosity or even delusions.One of the important early symptoms of a manic episode is the decreased need for sleep, to the point that many manic patients may not sleep at all even for several days, without feeling any tiredness.Manic speech is characteristically rapid, loud, and difficult to interrupt. Manic patients are easily distractible and respond to both internal and external stimuli in a self- referential manner. In some cases, however, anxiety and feeling of suspicion can cause the verbal output of such individuals to be markedly decreased, with these findings occasionally leading to a misdiagnosis of this mental illness.Manic patients frequently show flight of ideas as evidenced by a nearly continuous flow of accelerated speech, with abrupt changes from one topic to another.Diagnostic classificationIn some bipolar patients, only one manic episode may occur in their lifetime.Therefore,ICD-10 classifies bipolar disorder into a single manic episode and bipolar affective disorder. In DSM-TR, four bipolar disorder categories are included