History of bipolar disorder
Few disorders throughout history have been described with such consistency as bipolar disorder has been. Symptoms that characterise the illness can be found in medical literature throughout the centuries from the ancient Greeks to the present era.
Pre-19th Century and Melancholia
During Ancient Greece the ideologies held on mental disorder were surprisingly similar to modern day rhetoric of mental illness. Melancholia was described as the psychological expression of an underlying biological dysfunction specifically a disturbance of the brain.
Hippocrates in the 4th and 5th centuries BC argued for this more biological origin of mental disorders and against the popular explanation given to most ills as a manifestation of magical or supernatural forces. His arguments were compatible with the then dominant humoural theory. The theory proposed that a disturbance in the equilibrium of the four humours - blood, yellow bile, black bile and phlegm. The excess of black bile was seen as the underlying cause of melancholia whereas mania was attributed to an increase of yellow bile. Aristotle in contrast to Hippocrates saw the heart rather than the brain as the impaired organ responsible for the illness. He proposed that all humans had small amounts of black bile but an excess of this was seen in melancholia. A temperament he also associated with the gifted.
It was not until the 2nd century AD, that Aretaeus of Cappadocia actually suggested that mania was an end-stage process of melancholia. He described cyclothymia as a form of mental disease alternating between periods of depression and mania.
Middle Ages
The Middle Ages was a time governed by religious zealotry. The monasteries perpetuated mental illness as a form of a punishment for some wrongdoing. It was not until the 17th century that the religious overtones in psychiatry abated and clinical observations were once more feverishly pursued. The protagonist in this upsurge was Felix Platter whose paper in 1602 included descriptive clinical observations as well as a classification of mental disorders. This cascaded into a surge of publications reporting different disease categorisations for many of the clinical observations made. This trend of over classification threatened the possibility of a constructive diagnostic criterion for mental disorders that was logical and meaningful.
19th century
The 19th century set the groundwork for modern perspectives of bipolar disorder. Led by works of Falret and Baillarger who both independently suggested that mania and depression were different expressions of the same disease. Nonetheless subtypes of bipolar disorder were also recognised early on. For example Hypomania was described as 'that form of mania that typically shows itself only in the mild stages abortively, so to speak" (Mendal 1881). Cyclothymia was also described as episodes of both depression and mania that did not end up as dementia (Kahlbaum 1882). However even with the recognition that bipolar disorder had a course the prevailing dominant view was still that mania and melancholia were separate entities.
Kraepelin
Kraepelin was the first to segregate the psychotic disorders and draw boundaries around their clinical diagnoses. The dominance of melancholia in psychiatry was such that it was not until the eight edition of his textbook that Kraepelin included the category of modern day manic depression. It was in this rendition that manic-depression disorder subsumed all notions usually circumscribed under melancholia (e.g. milder depressive disorders).
By isolating the disorders Kraepelin further delineated dementia preacox (now referred to schizophrenia) from manic depression. He was also the first to introduce the concept of psychological stresses. He argued that psychological and social variables together with biological vulnerabilities played an influential role in the onset of an episode.
Evolution of Bipolar Disorder in Europe and America
During the 1950's the concept of manic depression in America and Europe began to diverge (Pichot 1988). This separation engendered different perspectives in the importance of particular diagnostic features and treatment choices.
America, led by the ideas of Adolf Meyer (Meyer 1950-52), took the perspective that mental disorders were an interaction of an individual's biological and psychological features and their social environment. With the rise of psychoanalytical thinking manic depression was defined in terms of the individual and his environments. This became the main focus for diagnosis and treatment whilst clinical symptomology and the course of the illness were relatively ignored. By contrast, Europe remained faithful to the disease model. This approach focused on the aetiology of the functional psychoses and postulated that clinical manifestations were to be understood on the basis of specific natural history and pathophysiology. Nevertheless the failure to identify mechanisms underlying pathogenesis cast doubt over the usefulness of this theory. It was the biological hypothesis (e.g. genetic vulnerability) that became a more favourable alternative. Unlike in America, Europe still regarded psychiatry and psychoanalytic thought as distinct and separate fields.
The Continuum Theory
Eugen Bleuler (1924) was the first to suggest that manic depression and dementia praecox (schizophrenia) were on a continuum with blurred boundaries. He hypothesised that patients were distributed along a spectrum and that the person could be on a different point on the spectrum at different times. The individual was characterised as either being predominantly schizophrenic or predominantly bipolar. Bleuler extended Kraeplin's concept of manic depression into subcategories that anticipated the future sub-types classified within bipolar disorder and the bipolar-unipolar distinction.
The Unipolar Concept
Leonhard (1957) pioneered the first classification system that went beyond clinical description alone. His observations led him to the term bipolar in describing patents with a history of mania and a higher incidence of mania in their families compared to patients who only experienced depression (whom he termed monopolar). Family studies further supported this differentiation and helped validate an independent diagnostic criterion - family history ( Angst 1966 & Perris 1966). The distinction between the bipolar-unipolar concept was first officially introduced in to the American classification system (DSM III) in 1980 and has been explicitly named in the International Classification of Diseases Manuel (ICD-10-World Health Organisation).
Originally both bipolar and unipolar concepts were used to describe patients with an illness course of recurrent episodes characterised by clear functional impairment. Confusingly, unipolar disorder has also been used to describe depressed patients without a history of mania or hypomania. However evidence attained from pharmacological, biological, psychological and social research (Goodwin & Jamison, 1990) attests that these two illnesses are on a continuum with bipolar at one end and unipolar at the other.
Subtypes with Bipolar Disorder
Bipolar disorder has been divided into different subtypes (Dunner et al 1976). Generally Bipolar-I patients are characterised with a history of mania severe enough to warrant treatment. Psychosis is frequently evident in manic episodes. Bipolar II patients experience episodes of hypomania, behaviours that are aberrant from normal behaviour but not acute enough to require hospitalisation. Evidence has also found an overlap in family history between both forms of the disorder that further supports the belief that both are part of the same continuum.
Further Differentiations of Bipolar-II Disorder
The classifications of the milder forms of bipolar-II disorder have been inconsistent. To eliminate such ambiguity a nomenclature system for the milder forms of depression and mania was proposed (Angst 1978). Bipolar patients were divided into Md and mD, with M (mania) and D (depression) indicating an episode that required hospitalisation and m and d describing behaviour that could be clearly differentiated from normal behaviour but not severe enough to merit hospitalisation. Other studies have used alternative taxonomy in classifying different subtypes of bipolar-II patients that only confuses matters further.
The 'dm' group illustrated in diagram 1 characterises patients who alternate between mild forms of depression and mild forms of mania. These are usually never severe enough to necessitate hospitalisation. Other researchers have categorised these patients with cyclothymia. Research into this group shows a family history and pharmacological characteristics similar to that seen in bipolar disorder. That affirms that this disorder is part of the bipolar spectrum ( Akiskal 1977 & Egeland 1983).
Conclusions
Bipolar affective disorder has a long established history that spanned across the centuries. Although for much of that time mania and depression were regarded as separate disease entities rather than as diverse expressions of the same illness. The distinction between the bipolar-unipolar concepts has engendered much research into the plausibility of the continuum theory. The complexities and subtle variations found within the bipolar spectrum makes it difficult to obtain a lucid explanation of its origin, course and outcome. It is hopeful however with the advantage of hindsight and the advancement in diagnostic techniques that future research will be able to elucidate a clearer understanding of the illness. That will help to define the subtypes and develop appropriate treatments accordingly.
References
Akiskal, H.S, Djenderedjian, A.H, Rosenthal, R.H, Khani, M.K. (1977) Cyclothymic disorder: Validating criteria for inclusion in the bipolar affective group. Journal of American Psychiatry 134: 1227-33
Akiskal, H.S, Khani. M.K, Scott-Strauss, A. (1979) Cyclothymic temperamental disorders. Psychiatric Clinical North American 2: 527-554
Angst, J. (1966) Zur Atiologie und Nosologie endogener depressiver Psychosen Berlin: Springer
Angst, J. (1978) The course of of affective disorders II: Typology of bipolar manic-depressive illness Arch Psychia Ner226(1): 65-73
Bleuler, E. (1924) Textbook of Psychiatry. English ed by A.A. Brill. New York:
Dunner, D.L, Gershon, E.S, Goodwin, F.K. (1976) Heritable factors in the severity of affective illness Biological Psychiatry 11: 31-42
Egeland, J.A, Hostetter, A.M, Eshleman, S.K. (1983) Amish study III: The impact of cultural factors on diagnosis of bipolar illness American Journal of Psychiatry 140: 67-7 1
Goodwin, F.K, Jamison, K.R. (1990) Manic-Depressive Illness New York: Oxford University Press
Kahlbaum, K.L. (1882) Uber cyclisches Irresein Der Irrenfreund 10: 145-157
Leonhard, K. (1957) The Classification of Endogenous Psychoses. 5th ed. Eli Robins ed. Berlin:
Mendal, E. (1881) Die Manie Vienna: Urban and Schwarzenberg
Meyer, A. (1950-52) Collected Papers of Adolph Meyer. EE Winters, ed. Baltimore: John Hopkins Press
Perris,C, ed. (1966) A study of bipolar (manic-depressive) and unipolar recurrent depressive psychoses Acta Psychiatr Scand. 42 (suppl 194)
Pichot, P. (1988) European perspectives on the classification of depression British Journal of Psychiatry 153(Suppl 3): 11-15
Torrey, E.F. (1999) Epidemiological comparison of schizophrenia and bipolar disorder Schizophrenia Research 39: 101-106
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