Über die Autorin bzw. den Autor

Mick Power is Professor of Clinical Psychology and Director of the Clinical Psychology Training Programme at the University of Edinburgh. He is a practicing clinical psychologist in the Royal Edinburgh Hospital. In the past he has been a Senior Lecturer at the University of London and has worked as a clinical psychologist at Guy's Hospital, and at the Bethlem and Maudsley Hospitals. He has worked for the Medical Research Council and has acted for many years as a Research Adviser to the World Health Organization. He is a founding editor of the journal Clinical Psychology and Psychotherapy.

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"This handbook gives an outstanding overview of the accomplishments to date and a sense of the excitement to come."
Kay Redfield Jamison, Foreword

Mood Disorders: A Handbook of Science and Practice provides an up-to-date summary of the latest theory and practice in unipolar and bipolar mood disorders.

This comprehensive volume focuses on innovations in both science and clinical practice, and considers new pharmacological treatments as well as psychological therapies.

With contributions from the world's leading authorities on mood disorders, all clinical psychologists and psychiatrists in practice and training will find this book an authoritative reference tool.

Aus dem Klappentext

"This handbook gives an outstanding overview of the accomplishments to date and a sense of the excitement to come."
Kay Redfield Jamison, Foreword

Mood Disorders: A Handbook of Science and Practice provides an up-to-date summary of the latest theory and practice in unipolar and bipolar mood disorders.

This comprehensive volume focuses on innovations in both science and clinical practice, and considers new pharmacological treatments as well as psychological therapies.

With contributions from the world's leading authorities on mood disorders, all clinical psychologists and psychiatrists in practice and training will find this book an authoritative reference tool.

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Mood Disorders

John Wiley & Sons

Chapter One

Paul Bebbington

INTRODUCTION

In this chapter, I will deal with the difficult problem of classifying a disorder that looks more like the expression of a continuum than a useful category. The way affective symptoms are distributed in the general population calls into serious question the utility of a medical classification, and certainly makes procedures of case definition and case finding very difficult. Nevertheless, researchers do rely on these procedures to establish the epidemiology of the disorder, and in the second part of the chapter I will pull together recent findings on the prevalence and distribution of unipolar depression.

CLASSIFICATION AND UNIPOLAR DEPRESSION

The idea of unipolar depression is primarily a medical one; that is, it involves a particular way of looking at psychological disturbance. This centres on the notion of a syndrome that is distinct from other psychiatric syndromes. Some of these can be relatively easily distinguished-for example, paranoid schizophrenia-while others are acknowledged to be related. The disorders that most resemble unipolar depression are other affective disorders, that is, conditions that are characterized centrally by mood disturbance. They cover a number of anxiety disorders, other depressive conditions, and bipolar mood disorder.

Bipolar disorder is identified by the presence of two sorts of episode in which the associated mood is either depressed or predominantly elated. It is distinct from unipolar disorder in a variety of ways (such as inheritance, course, and outcome), and the distinction is therefore almost certainly a useful one. However, depressive episodes in bipolar disorder cannot be distinguished symptomatically from those of unipolar depression. As perhaps half of all cases of bipolar disorder commence with a depressive episode, this means that unipolar depression is a tentative category-the disorder will be reclassified as bipolar in 5% of cases (Ramana & Bebbington, 1995).

Psychiatric disorders are classified in the hope that the classification can provide mutually exclusive categories to which cases can be allocated unambiguously (case identification). Categories of this type are the basis of the medical discipline of epidemiology, which is the study of the distribution of diseases (that is, medical classes) in the population. This has been a very powerful method for identifying candidate causal factors, and is thus of great interest to psychiatrists as well as to clinicians from other specialities.

Syndromes are the starting point of aetiological theories, and of other sorts of theory as well-theories of course and outcome, of treatment, and of pathology (Wing, 1978). There is no doubt that the medical approach to malfunction has been a very effective one, generating new knowledge quickly and efficiently by testing out theories of this type (Bebbington, 1998).

SYMPTOMS AND SYNDROMES

The first stage in the establishment of syndromes is the conceptualization of individual symptoms. Symptoms in psychiatry are formulations of aspects of human experience that are held to indicate abnormality. Examples include abnormally depressed mood, impaired concentration, loss of sexual interest, and persistent wakefulness early in the morning. They sometime conflate what is abnormal for the individual and what is abnormal for the population, but they can generally be defined in terms that are reliable. Signs (which are unreliable and rarely discriminating in psychiatry, and thus tend to be discounted somewhat) are the observable concomitants of such experiences, such as observed depressed mood, or behaviour that could be interpreted as a response to hallucinations. Different symptoms (and signs) often coexist in people who are psychologically disturbed, and this encourages the idea that they go together to form recognizable syndromes. The formulation of syndromes is the first stage in the disease approach to medical phenomena, as syndromes can be subjected to investigations that test the various types of theories described above.

While syndromes are essentially lists of qualifying symptoms and signs, individuals may be classed as having a syndrome while exhibiting only some of the constituent symptoms. Moreover, within a syndrome, there may be theoretical and empirical reasons for regarding some symptoms as having special significance. Other symptoms may be relatively nonspecific, occurring in several syndromes, but, even so, if they cluster in numbers with other symptoms, they may achieve a joint significance. This inequality between symptoms is seen in the syndrome of unipolar depression: depressed mood and anhedonia are usually taken as central, while other symptoms (such as fatigue or insomnia) have little significance on their own. This reflects serious problems with the raw material of human experience: it does not lend itself to the establishment of the desired mutually exclusive and jointly exhaustive categories.

In an ideal world, all the symptoms making up a syndrome would be discriminating, but this is far from true, and decisions about whether a given subject's symptom pattern can be classed as lying within a syndrome usually show an element of arbitrariness. The result is that two individuals may both be taken to suffer from unipolar depression despite exhibiting considerable symptomatic differences.

This is tied in with the idea of symptom severity: disorders may be regarded as severe either from the sheer number of symptoms, or because several symptoms are present in severe degree. In practice, disorders with large numbers of symptoms also tend to have a greater severity of individual symptoms.

COMPETING CLASSIFICATIONS

The indistinctness of psychiatric syndromes and of the rules for deciding whether individual disorders meet symptomatic criteria has major implications for attempts to operationalize psychiatric classifications. There are currently two systems that have wide acceptance, the Diagnostic and Statistical Manual (DSM) of the American Psychiatric Association (APA) and the World Health Organization (WHO)'s International Classification of Disease (ICD). In the early days, revision of classificatory schemata relied almost wholly on clinical reflection. However, since the classifications are set up primarily for scientific purposes, they should properly be modified in the light of empirical research that permits definitive statements about their utility. The standardized and operationalized classifications that are now in existence offer an opportunity for using research in this way.

Unfortunately, much of the pressure for change has continued to originate from clinical and political demands. Revisions have sometimes had the appearance of tinkering in order to capture some imagined essence of the disorders included (Birley, 1990). What looks like fine-tuning can nevertheless make considerable differences to whether individual cases meet criteria or not, and thus disproportionately affects the putative frequency of disorders. We should jettison classifications only on grounds of inadequate scientific utility and as seldom...