The first systematic descriptions considered depression and mania as part of the same clinical entity and begun with observations performed by Aretaeus of Cappodocia in the II Century A.D. Posteriorly, in the XIX Century, the first detailed clinical descriptions of the "Folie Circulaire" by Falret and the "Folie a double forme" by Baillarger were reported. However, it was Emil Kraepelin who defined with precision the boundaries of this disease and included forms of mania and depression in one single clinical entity know as manic-depressive psychosis. Until this time, affective disorders were conceptually understood as a continuum within a single clinical entity [24]. In the second half of the XX Century, Leonhard and others proposed the existence of two different disorders: mainly Unipolar affective disorders and Bipolar affective disorders.
Lately reports of International Diagnostic Classification Systems have emphasized, for better understanding of Unipolar and Bipolar affective disorders, that these are two different clinical entities in their clinical presentation and also in evolution. This diagnostic perspective has demonstrated its validity in different studies that have been replicated and that are essential at the time of defining therapeutic strategies.
Epidemiology
Bipolar Affective Disorder is present in all cultures and races with a similar prevalence of 1.6% [23]. However, studies that considered all the range of bipolar spectrum, report a lifetime prevalence fluctuating between 3.7% and 6% [19]. On the other hand, the female/male affected ratio varies from 1.3 to 2.1 respectively. Although bipolar disorder can develop at any age, the peak period of onset is between the ages of 15 and 19 years. More interesting, 59% of a studied sample experienced their first bipolar symptoms during childhood or adolescence [8, 25].
Clinical Manifestations
Bipolar affective disorder is defined as a group of diseases with a common factor of one manic or hypomanic episode during its evolution and episodes of opposite affective polarity. Therefore, the classical description of Falret and Kraepelin recognizes the presence of clinical differences in depression, mania, hypomania, mixed phases and asymptomatic interphases of remission.
DSM-IV describes 4 types of Bipolar Affective Disorders:
Bipolar Affective Disorder I
Corresponds to the classically described disease of manic-depressive psychosis. The characteristic is at least one manic episode associated or not associated to episodes of hypomania, depression or mixed phases. Mania is defined as a psychopathological state characterized by 3 central elements: Pathologically elevated mood, increased motor activity and grandiosity ideas. Parallel to these, it is frequent to observe acceleration in the speed of speech and thoughts, loss of subtle clues that are necessary for social interaction, increased sexual arousal, hyperphagia, insomnia and psychotic manifestations. From the affective point of view it is also possible to observe irritability and rage following minimal stimulation. Two characteristics of importance in the majority of manic episodes is the loss of insight and impairment of social and labour relations. This situation implies serious consequences to the patient and its environment.
Bipolar Affective Disorder II
Describes the group of patients that present major recidivant depressive episodes alternating with hypomanic phases of at least 4 days duration. By definition, Bipolar Affective Disorders II do not present periods of mania nor mixed phases. The concept of hypomania refers to a phase characterized by pathologically elevated mood of minor to moderate intensity, increase of energy and physical activity and optimistic mood not frequently seen in the patient. During the episode of hypomania there is preservation of insight without an impairment of social or labour performance [18].
Ciclotimic Disorders
It refers to a group of patients that present cyclical variations of mood characterized by numerous periods of hypomanic symptoms of less than 4 days duration, alternating with periods of depressive symptoms that are not severe enough to constitute a major depressive episode [3]. The first descriptions by Kraepelin considered ciclotimia as a form of temperament that predisposed patients to frequent fluctuations of their psychic state.
Non specified Bipolar Affective Disorders
Includes abnormalities characteristic of bipolar disorders that do not comply strictly with criteria defined by the 3 types of bipolar disorders previously described.
