Bipolar disorder

Chapter 12
Bipolar disorder: A troubled diagnosis


Gin S. Malhi1 and Michael Berk2


1 Professor and Chair, Department of Psychiatry, Sydney Medical School, University of Sydney, Sydney, Australia


2 IMPACT Strategic Research Centre, Deakin University, Department of Psychiatry, Orygen Research Centre, and The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Australia


Introduction


Bipolar disorder is one of the most interesting and talked about psychiatric diagnoses of our times, and the stories of its inception and its current positioning within psychiatric classification serve to highlight a number of fundamental problems with psychiatric taxonomy [1].


Despite assiduous efforts to better delineate and understand bipolar disorder, especially over the past two decades, it remains poorly defined and some would argue that its boundaries have become less well delimited and that it has become a more nebulous concept. Consequently, advances in the management of bipolar disorder have been stilted and slow, and patients who attract this diagnosis continue to face the prospect of a chronic illness with often-unsatisfactory outcomes. This chapter briefly traces the history of this troublesome diagnosis and examines those aspects that continue to cause confusion and concern.


Manic-depressive illness


Early observations


When considering the history of an illness, it is important to recognize that the views of many ancient physicians and philosophers concerning mental phenomena, although they may appear to correspond to our contemporary understanding of an illness, almost certainly referred to symptoms, signs, and behaviours associated with diseases of very varied and altogether different origin. For example, a large variety of infections, left unchecked, can cause marked fever and delirium, which often mimic symptoms of both mania and depression.


Some of the earliest written descriptions of melancholia were penned in ancient Greece by Hippocrates of Cos (460–377 BC) and members of his school who alluded, for example, to irritability, despondency, and an inability to sleep or eat. Interestingly, these writers argued strongly that mental illnesses, such as mania and melancholia, stemmed from organic causes and reflected brain dysfunction, in opposition to the prevailing view of the time, which explained mental illnesses in magical or supernatural terms. Hippocrates considered the brain to be pivotal to the generation of emotions and rejected the role of divine forces [2]. Unfortunately, these ideas, which seem at first sight to correspond to our own modern-day thinking, were based on wholly inaccurate biological models that survive metaphorically. Plato’s (428–348 BC) theory of ideas incorporated rationalism, which has many parallels with modern thinking. He postulated that non-material abstract forms or ideas possess the highest and most fundamental kind of reality. Plato gave psychological importance to childhood trauma and asserted that the psychological significance that people assign to events is more important than the actual events themselves.


The humoral theory, adopted by physicians from Hippocrates until the 19th century, attributed health and disease to a delicate balance between the four humours: blood, phlegm, yellow bile, and black bile. Mania was thought to occur because of excess yellow bile, whereas an over-secretion of black bile (melaina chole) from the liver was thought to culminate in melancholia. As with modern physicians, ancient thinkers and great philosophers did not always agree: Aristotle (himself a student of Plato and tutor to Alexander the Great) assigned much more importance to the heart than he did to the brain. Nonetheless, when considering causality, he too believed that melancholia was a consequence of excess black bile. It was Aristotle who developed the quite visionary concept that some individuals are somehow predisposed to melancholia. He further linked this concept to temperament and, with this coruscating insight, anticipated much of our current ideas regarding biomarkers, vulnerability, and the role of personality and functioning in relation to the mental illnesses of today [3, 4].


Following on from these early concepts, subsequent observers tentatively linked mania and melancholia, suggesting that both either followed similar trajectories or were in fact the same illness, happening to present in varied forms or at different stages of disease. Aretaeus of Cappadocia, who suggested that mania was the end stage of melancholia, made the first definitive link between the two conditions [5]. A physician in Rome during the second century AD, he viewed “mania as a variety of melancholia” and described it as an alternating pattern of illness in which an individual could oscillate between the two forms. Remarkably, he also alluded to cyclothymia and described how personality could, perhaps, contribute to intermittent presentations of manic symptoms. Aretaeus’ rich descriptions of mania detailed a spectrum that overlapped with psychosis, but he only associated the classical form of mania with melancholia. Prophetically, Aretaeus regarded mania as a disorder of the brain, and thus linked it, both phenomenologically and etiologically, to melancholia, which was also of endogenous origin [6].


Other aspects of the mood disorders, as we know them today, were successively added over time as physicians continued to observe patients with mental illness. Galen of Pergamon (AD 131–201), for example, drew out the recurrent nature of melancholia and established it as a chronic condition. But despite these many early insights, the concepts of mania and depression failed to develop further as medicine, and indeed science as a whole, fell prey to religious and spiritual thinking. During these “dark ages,” divinity dominated and mental signs and symptoms were blamed on any number of evil forces, supernatural events, or black magic. Despite the Renaissance, not until the 19th century did a more informed discussion regarding melancholia and mania resume [7].


Great minds thinking alike


In the middle of the 19th century, two French physicians had the same idea at the same time. Both linked mania to depression and, in essence, created the concept of manic-depressive illness. Jean-Pierre Falret termed his interpretation la folie circulaire (circular disorder), which he used to describe a regular continuous succession of mania and depression [8]. Simultaneously, Jules Baillarger described la folie double forme (double insanity), a single illness in which both mania and depression could be manifested [9]. Wilhem Griesinger echoed this union although, more in tune with Aretaeus’ thinking, he formulated mania as the end stage of a progressively worsening melancholia, and thus viewed the two presentations as manifestations of the same entity occurring at different epochs of the illness. Griesinger regarded the illness as having a chronic course that invariably eventuated in a poor outcome. In contrast, Ludwig Kahlbaum and Ewald Hecker identified much milder forms of “circular disorders,” which also manifest an alternating pattern, but which do not develop a chronic course or culminate in dementia [10, 11]. Again, the descriptions by these early observers are prescient of today’s mood disorder subtypes, such as bipolar II disorder and cyclothymia. However, it is noteworthy that not everyone was in concordance with these ideas: many physicians still regarded mania and melancholia as quite separate illnesses with distinct trajectories.


It was at this juncture that Emil Kraepelin synthesized the observations and insights of his predecessors and contemporaries by creating a model that remains with us today [12]. Kraepelin gave definition to manic-depressive illness by separating it from dementia praecox. As it gradually crystallized and took form as a diagnosis, its boundaries underwent gradual successive expansion until manic-depressive illness eventually consumed all forms of melancholia. Kraepelin’s differentiation of manic-depressive illness from dementia praecox (subsequently known as schizophrenia) was predicated on the former being more likely to: (1) have a family history of manic-depressive illness, (2) run a relatively benign course and have a benign prognosis, and (3) manifest an episodic or cyclical pattern of illness. Kraepelin’s model was widely adopted and remains a principal driver in psychiatric classification today. One reason for its success is its relative simplicity, along with the fact that it arose from empirical observations and therefore resonated strongly with clinicians. Another advantage that perhaps also contributed to its popularity and longevity is that it allowed the inclusion of additional causal factors, both psychological and social. It was, therefore, a relatively holistic model, and one that provided an accessible framework for interrogating mental phenomena [13].


Despite a common ancestry, ideas concerning manic-depressive illness developed along different lines in Europe and the United States [14]. In the latter, psychoanalysis played a significant role, along with social and psychological factors, partly because of Adolf Meyer’s influence and emphasis on bio-psychosocial factors, which he termed “ergasiology” [15], and partly because, at the beginning of the 20th century, treatments that were derived from the disease model were largely ineffective. In contrast, European psychiatry maintained allegiance to the medical model of disease, and concepts of manic-depressive illness grew independently from both psychoanalytical and psychosocial schools of thought.


Bipolar disorder


Birth and adoption


In 1957 Karl Leonhard (1904–1988) noted that patients with manic-depressive illness could be separated into those that experienced only depression and those that experienced both mania and depression. He called these two groups monopolar and bipolar, respectively, and thus in effect coined the bipolar descriptor [16]. This separation was subsequently validated by studies based on family history [17, 18]. However, it is important to note that the terms actually refer to two kinds of recurrent affective disorders. This nuance was lost in the DSM classification of bipolar disorder, which adopted this nosology but which, instead of prioritizing cyclical recurrence, emphasized polarity.


The term bipolar disorder appeared in DSM-III in 1980. This edition of DSM was the first to recognize the unipolar–bipolar distinction proposed by Leonhard two decades earlier. However, use of the term failed to permeate into clinical practice for quite some time, and the diagnosis of manic-depressive illness remained in use, alongside bipolar disorder, until 1992, when the publication of ICD-10 finally led to its more widespread adoption [7].


Within DSM, bipolar and depressive disorders are partitioned on the basis of manic symptoms; but this classification fails to accommodate the many unipolar depressed individuals who have a recurrent form of affective illness. For example, in DSM-IV, two episodes over a lifetime qualify for the description of “recurrent unipolar depression” but because “two or more” is a very broad range, and one that encompasses virtually all depressed patients encountered in clinical practice, it is in effect a meaningless descriptor. These and other problems remain in the latest edition of DSM.


DSM-5


Published in 2013, the most dramatic change in DSM-5 in relation to bipolar disorder is its repositioning relative to other groups of disorders [19]. In DSM-IV the chapter on mood disorders contained both depressive and bipolar disorders [20]. However, in DSM-5, bipolar and related disorders are assigned a separate chapter, between depressive disorders and schizophrenia spectrum and other psychotic disorders, purportedly to reflect its genetic and phenomenological linkages to both sets of disorders. This displacement in classification is significant because it suggests that bipolar disorders are fundamentally distinct from depressive disorders, but in reality this may not be the case.


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May 29, 2017 | Posted by in PSYCHIATRY | Comments Off on Bipolar disorder
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