Biological psychiatry in perspective - British Medical Bulletin

Biological psychiatry in perspective MGGelder Oxford University Department of Psychiatry, Warneford Hospital, Oxford, UK

Biological psychiatry is a technical term that denotes physiological and biochemical approaches to psychiatric aetiology and, despite the usual wider meaning of the word biological, excludes psychosocial approaches/Biological' causes of severe psychiatric disorder have been suspected from the earliest times, and in some periods an excessive focus upon them has led to neglect of psychological and social approaches to treatment, to the detriment of patients. It is important that current research into biological psychiatry should be carried forward in conjunction with the important advances that have been made in psychological and social research.The causes of psychiatric illness are complex and it is unlikely that any single approach, biological or psychosocial, will be sufficient on its own.The great potential of biological psychiatry will be realized only if it is viewed within these wider historical and scientific perspectives.

The term biological psychiatry often puzzles those who are working in other branches of science and medicine. The word biology refers to the study of living things and therefore encompasses physiological, biochemical and psychological forms of investigation. In psychiatry, however, it has become conventional to use the term biological to encompass physiological, biochemical and genetic studies in contrast to social and psychological investigations. The general reader who is coming for the first time to the subject of this volume should understand this convention and should view the studies described in this volume in the context of psychological and social investigations. The general reader should also keep in the mind two other perspectives, the historical and the scientific.

The historical perspective From the earliest times, it has been recognised that mental disorders have both physiological and psychological causes. In Hippocratic writings of Postal addrets: the 4th century BC, serious forms of mental illness were ascribed mainly Professor M G GeMer, t o somatic causes, which were expressed in the then current ideas that health n. - ^ ^ T T ? depended on a correct balance of the four body humours (blood, Department of Psychiatry,

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Biological psychiatry

term melancholia. These ideas were overtaken in the middle ages by the view that mental illness could best be explained in religious terms of sin and evil but in the 17th and 18th centuries interest in physical causes of severe illness revived. The causes were now sought in the brain itself, although the nature of this brain disorder was not understood. Repeated searches failed to show specific pathological changes even with the use of the new science of neuropathology developed in the 19th century. At that time, another aetiological theory came to the fore. It has long been recognized that mental illness tends to run in families, but, in 1809, the French psychiatrist Morel suggested that the disorder became more severe in successive generations of the same family and he suggested that inheritance can interact with certain adverse environmental factors, such as abuse of alcohol, and that the resulting changes could be transmitted to the next generation. This idea, which seems improbable today, was consistent with the then current notions of inheritance of acquired characteristics. These views had two unfortunate effects: they led to therapeutic pessimism and they gave support to the eugenic movement which held that the mentally ill should be separated from society and prevented from reproducing. The story of this period of research is an important reminder that scientific advances uncritically accepted can lead to harmful as well as to beneficial changes in policy. Although ideas concerning the aetiology of severe mental illness were dominated by these neuropathological and genetic theories, it is notable that practising doctors were aware that these ideas could not satisfactorily explain the illness of their patients. For example, the French psychiatrist Esquirol, writing in 1845, recognized the importance of heredity but stressed that psychological and social factors could predispose to or precipitate illness. Among his examples of adverse psychosocial factors were domestic problems, disappointments in love, and 'reversals of fortune', and he recognised also a wide group of physical causes such as the abuse of alcohol, the effects of childbirth and lactation, and epilepsy. The German psychiatrist Wilhelm Griesinger writing later in the century put forward similar views in his influential textbook The Pathology and Therapy of Mental Disorders. He wrote1: A closer examination of the aetiology of insanity soon shows that in the great majority of cases it was not a single specific cause under the influence of which the disease was finally established but a complication of several, sometimes numerous causes, both predisposing and exciting. Very often the germs of disease are laid in those early periods of life from which the commencement of the formation of character dates. It grows by education and external influences. 402

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Biological psychiatry in perspective

This statement still rings true today and could form a useful background to the studies described in this volume. Despite these wise and balanced views, many of the doctors who cared for the mentally ill in the second half of the 19th century took a simplistic organic view. The problem was recognised by Adolf Meyer, a Swiss doctor who became the dominant figure in American psychiatry in the late 19th and early 20th century. In the course of medical training in Switzerland, Meyer had been taught to think of aetiology in the tradition of Griesinger. When he began work in American psychiatric hospitals, he was disturbed by the narrowly organic views about aetiology and the consequent therapeutic nihilism. Meyer set out to promulgate the idea that mental illness had multi factorial causes and that, even in cases with the most obvious organic aetiology, there were additional psychosocial factors which could often be modified to the benefit of the patient. Meyer called this balanced approach psychobiology, a name that resembles the modern term biological psychiatry but had an altogether wider meaning embracing a detailed knowledge of each patient's biography and the educational and external influences that Griesinger had emphasized. Meyer's psychobiology had a beneficial effect on the practice of psychiatry by bringing about more active programmes of rehabilitation and resettlement and a better understanding of the psychological and social causes of mental illness. Its effects on research were less desirable, because psychobiology was so general and all-embracing it did not provide a clear guide to priorities in research. In the 1930s, neuroscience was in an early stage of development and this approach to psychiatric research together with Meyer's psychobiology were overtaken by psychoanalysis, which seemed at the time to provide answers to clinical problems which more scientific approaches could not rival. The gradual development of better methods of investigation, coupled with the discovery of drugs with powerful effects in the psychoses, led to a growing interest in the biological psychiatry which eventually expanded rapidly as new techniques of brain investigation became available. These few landmarks in the history of ideas about the causes of mental illness point to an important general conclusion. Each generation has based ideas of aetiology on the scientific approaches that were most active and seemed most plausible at the time. This sometimes led to a narrow view of aetiology, in which other factors, less easy to investigate, were neglected. Although, as the above quotations show, observant clinicians have always been aware of the complexity of the causes of psychiatric disorders in their patients, others have neglected the wider causes to the detriment of their patients. This volume reflects the wider viewpoint for it contains articles on psychological approaches as well as genetic, biochemical and physiological methods. Nevertheless, the reader Bnh(hMei£cat Bulletin 199632 (No. 3)


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Biological psychiatry

should bear in mind the wealth of research into social and psychological causes of severe mental illness that cannot be reviewed here.

The scientific perspective Three features of causation in psychiatry create difficulties for biological research: causes may be remote in time; one cause may have several effects; and one effect may have many causes. The causes of psychiatric illness are often remote in time. It has long been recognized that experiences in childhood can affect personality development and response to stress and it now seems possible that events before or soon after birth may be a primary cause of schizophrenia acting perhaps upon the development and maturation of the brain. The details of the process cannot be explained at present, but the general model has an obvious parallel in epilepsy in which trauma to the brain may result in disorder many years later. Nevertheless, it is very difficult to carry out direct scientific tests of associations so far apart in time. In the case of schizophrenia, indirect evidence has been called upon, for example the absence of gliosis in areas of the brain showing structural changes, a finding which suggests a pathological change before or around the time of birth2. A second source of indirect evidence is the study, in the brains of schizophrenics dying of other causes, of genes known to be involved in brain development (see for example3). A second difficulty for biological research is that in psychiatry a single cause can have multiple effects. This is illustrated by the consequences of syphilitic infection of the brain. When neurosyphilis was common, psychiatrists recognized that it could lead to dementia, affective symptoms, or a features resembling those of schizophrenia. Similarly, Huntington's chorea, which is due to a disorder involving a single gene and causing movement disorder and dementia, is associated also with psychiatric disorder including bipolar disorder4. With this diversity of manifestations of known single causes, it is difficult to decide what range of disorders should be included in an aetiological investigation. It has been suggested, on the one hand, that the whole spectrum of psychoses may have a common cause (see for example5) and, on the other, that these aetiological studies should consider specific subgroups within schizophrenia or manic depressive disorder. A third difficulty is that one effect may have multiple causes. There are predisposing, precipitating, and maintaining causes of psychiatric disorder; and there are usually psychological and social causes interacting with one or more genetic or biochemical cause of the same disorder. For example Kendler et al6 calculated that about half the liability to major 404

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