Delusions

Investigations Into The Psychology Of Delusional Reasoning

Philippa A. Garety, David R. Hemsley

• Publisher: Psychology Press
• Year: 2013
• Print ISBN:
  9781138152281
• eBook ISBN:
  9781135064280
• Topic: Medicine
• Subtopic: Psychiatry & Mental Health

The authors offer cogent reviews of the literature pertaining to the formation and maintenance of delusions, but the most substantial parts of the monograph expound the empirical inquiries which they and their colleagues have carried out in recent years. Most of the research has been published elsewhere, but such is the relevance of the experiments cited to the whole schema that the monograph has unique value. It is a synthesis which portrays the contribution to date of cognitive science to the biology and psychopathology of delusional thinking, and convincingly demonstrates that this way of looking at things has a considerable future. There are important implications for therapy as well as for hypothesis formulation. The monograph is attractively written, and the authors present their claims with exemplary modesty. The whole tenor of their approach gives weight to the conviction that here we have a story that must be taken seriously. It is a significant book, and I warmly commend it to all those with an interest in the future of psychopathology, and especially to psychiatrists who wish to advance their understanding of mental states and avoid stagnating with outworn dogma." - Robert Cawley, University of London in British Journal of Psychiatry Delusions are a key symptom of psychosis and yet there is no single book which considers delusions from a psychological perspective. In part this is because the syndrome of schizophrenia has captured the attention of many workers, and in part because delusions, as private mental phenomena, are not well suited to purely behavioural or observational methods of enquiry. For the past two decades, however, cognitive psychology has been in its ascendancy and delusions, as beliefs, are particularly amenable to investigation applying cognitive concepts and methods. Within this framework, it is possible to consider continuities between delusional and ordinary beliefs, as well as to seek to identify differences. This book, therefore, uniquely presents a psychological model of delusions, employing the neglected strategy of single symptom research and the tools of cognitive psychology

1 Concepts of delusion

Introduction

This book is about delusion, the psychiatric symptom which, for many, epitomizes madness. It is extremely common, and is present in a wide variety of conditions (Maher and Ross 1984). Definitions have, until recently, achieved a broad consensus within psychiatry (although they pose widely acknowledged social and political difficulties (Moor and Tucker 1979)). Standard definitions generally incorporate a proposition, explicit or implicit, concerning the irrationality of delusional beliefs. In this book, we propose that accepted concepts of delusions are inadequate, that the model of rationality they embody is outmoded, and that the reasoning of people with delusions is sometimes abnormal, but not in the way generally thought. Evidence will be presented to support this argument from reviews of existing literature and with data from four original studies.

Definitions

Many have written of delusion without attempting to define it (for example Arthur 1964), perhaps considering the dictionary definition sufficient: ‘a fixed false opinion with regard to objective things, especially as a form of mental derangement’ (Shorter OED, first found with this meaning in 1552). This concisely embraces the central characteristics of modern psychiatric definitions, which themselves derive from the work of the German phenomenologists of the late nineteenth and early twentieth centuries, among them Kraepelin (1899), Bleuler (1911) and, most importantly, Jaspers (1913).

Jasperian concepts

Jaspers begins his essay ‘Delusion and awareness of reality’ by stating that ‘to say simply that a delusion is a mistaken idea is firmly held by the patient and which cannot be corrected is superficial and incorrect. A delusion is a primary phenomenon — experiencing and thinking that something is real: this constitutes a transformation of one’s total awareness of reality.’ Jaspers is regarded (for example Schmidt 1940) as having made a breakthrough in the understanding of delusions by distinguishing, according to psychological criteria, between two classes of delusional ideas:

Some can be understood in the light of related affect, other experiences, hallucinations … others are not amenable to further psychological analysis but are phenomenologically irreducible. The former we call delusion-like ideas, the latter genuine delusional ideas … We would describe as genuine delusional ideas only those which have their manifest source in a primary pathological experience, or can be explained only in terms of a personality change. (Quoted by Schmidt 1940, p. 105)

This distinction between ‘primary’ and ‘secondary’ delusions has been extremely influential in psychiatry, although it continues to lack an empirical basis.

Delusions, Jaspers holds, are characteristically

• (1) held with extraordinary conviction, with an incomparable subjective certainty;
• (2) maintained imperviously to other experiences and compelling counter-arguments;
• (3) their content is impossible;
  and he emphasizes that
• (4) underlying all delusional judgements is a transformed experience of reality.

Jaspers goes on to describe in detail three subgroups of delusions proper: delusional perception, delusional idea or notion, and delusional awareness.

In delusional perception there is an immediately experienced change of meaning of a particular perception, though the perception itself remains unaltered. The basic feature is the ‘establishment of an unfounded reference’ (Gruhle 1915). A popular example (Arthur 1964) is of a man who looked at the marble tables in a cafe and suddenly became convinced that the end of the world was coming. It is important, as is claimed in this instance, that the tables are correctly perceived and appreciated and that the content of the delusion is incomprehensibly related to the patient’s life and situation.

Schneider’s original (1959) claim that it was possible to identify delusional perceptions by form alone, with no reference to content, is convincingly refuted by Spitzer (1990), who gives an example. In order to distinguish between a normal person who saw a black cat crossing her path on a Friday the 13th and thought it meant bad luck, and a schizophrenic patient who saw a black dog crossing his way and thought it meant the end of the world, criteria of ‘understanding’ and ‘cultural background’ have to be applied. ‘Delusional perceptions are neither unmistakable in form nor can one ignore their content’ (Spitzer 1990, p. 385). Spitzer instead suggests that because delusional perceptions are linked to some observable object they are more easily detected and less ambiguous than other delusional phenomena, and are therefore to be rated higher on a continuum of detection than other delusional items. ‘What we have in mind is not a clear-cut dichotomy, but rather a continuum, on which delusions may be placed, ranging from “very questionable, might be just ingenious, or might be just a religious phantasy” to “certainly delusional”.’ (Spitzer 1990, p. 386).

Jaspers’ sudden delusional ideas appear as sudden notions, new aspects and new meanings of remembered life experiences. Jaspers quotes a patient who wrote to him:

It suddenly occurred to me one night, quite naturally, self-evidently but insistently, that Miss L. was probably the cause of all the terrible things through which I had to go these last few years … if you examine it fairly you will see there is very little reflection about it; rather everything thrust itself upon me, suddenly, and totally unexpectedly, though quite naturally. I felt as if scales had fallen from my eyes and I saw why life had been precisely as it was …. (Jaspers 1913, p. 103)

Delusional awareness (Wahnstimmung) is characterized by a knowledge of immense and universal happenings without clear ideation or sensory perception. Merely thinking about things gives them a special significance, for they seem to be linked, in some way, with so many other things.

Central to Jaspers’ concept of delusion is incorrigibility. Decisive in characterizing this is not the subjective intensity of the experience but the maintaining of what is evident to the patient in the face of subsequent reflection and external criticism. Jaspers accepts that any individual may assert a truth against the beliefs of the majority, but for the deluded person the incorrigibility serves a particular interest: ‘The delusional content is of vital necessity … and without it he would inwardly collapse…. In the case of delusion, we may see someone irretrievably lost in untruth.’ (Jaspers 1913, p. 411).

Jaspers regards primary delusions as deriving from an alteration in the personality, the precise nature of which is unknown, or from a hypothetical disease process, and while the pre-morbid personality might explain the content or theme of the delusion it cannot explain the actual existence of a delusion. Thus, as Schmidt (1940) points out, if it were always possible to derive a primary delusion from one of the closely related primary symptoms with which it is intimately associated, or from some underlying disorder, then it would no longer be a primary but a secondary delusion, and there would be no such thing as a genuine delusion.

Spitzer (1992) suggests that Jaspers’ interest in dividing delusions into primary and secondary is best understood within the context of psychiatric knowledge at his time. The spirochete which causes syphilis had just been discovered and Jaspers expected that the pathogenic agent causing Kraepelin’s dementia praecox (Kraepelin 1899) would sooner or later be found. Meanwhile the diagnosis of such a disease process had to be based on psychopathology. The distinction between the understandable development of delusions (such as in mood disorders) and the non-understandable delusions caused by a supposed disease process was therefore of great importance.

Matussek (1952) has, however, argued that Jaspers’ approach of distinguishing between the ‘psychological irreducibility’ of some delusions and the understandable nature of others has had serious implications. It implies that the former phenomena can only be explained in organic terms, and discourages attempts to investigate their psychological structure regardless of cause.

Winters and Neale (1983) note that the distinction between primary and secondary delusions is less popular in German-speaking countries than it has been in Britain and the United States. They argue that the distinction is neither reliable, nor of any proven diagnostic significance, despite Schneider’s (1959) claim that delusional perception is of exceptional diagnostic importance to schizophrenia.

Delusional perception nonetheless remains an intriguing sub-type of delusion (or a point along the continuum) and it is possible that such delusions involve subtle alterations in perceptual qualities, such as vividness, in contrast to the grosser perceptual changes found in hallucinations.

Spitzer (1990) also considers in detail Jaspers’ three defining characteristics. The third characteristic, impossibility (or falsity) presents a number of problems, which are discussed below (pp. 5—6). Spitzer, however, notes that if one concentrates on falsity, one is likely to overlook the remaining two characteristics, subjective certainty and incorrigibility. These, he argues, when about the subject’s own mental states, are typical of normal people. ‘Statements like “I’m feeling pain” … or “I’m thinking at the moment” can be uttered by me with subjective certainty and incorrigibility and there is no way in which somebody could ever reasonably question these statements’ (Spitzer 1990, p. 390). Spitzer thus proposes, modifying Jaspers, that a delusion can be said to be present only when these two characteristics occur in beliefs about the external world, and not when the belief concerns the person’s own mental states.

Modern definitions

Definitions of delusions, as well as the primary/secondary distinction, reflect, in British and North American psychiatry, the profound influence of Jaspers, and standard definitions incorporate many of the characteristics of delusions that he described. Mullen offers the following definition in a textbook of psychiatry:

A delusion is an abnormal belief. Delusions arise from disturbed judgments in which the experience of reality becomes a source of new and false meanings. Delusions usually have attributed to them the following characteristics:

• (i) They are held with absolute conviction.
• (ii) They are experienced as self-evident truths usually of great personal significance.
• (iii) They are not amenable to reason or modifiable by experience,
• (iv) Their content is often fantastic or at best inherently unlikely,
• (v) The beliefs are not shared by those of a common social or cultural background. (Mullen 1979, p. 36)

Such a definition presents a number of difficulties. There is evidence (for example Strauss 1969) that many delusions do not show absolute conviction. Furthermore, psychiatric texts do not specify how ‘absolute’ conviction is to be assessed, whether by obtaining a simple statement of certainty or by a more rigorous test of the precise level of conviction. Secondly, while delusions are said to be ‘not amenable to reason’ (or incorrigible), criteria are again not laid down for assessing this: should the interviewer present compelling counterarguments, and, in such a context, what counts as ‘compelling’? The assessment of the fantastic or bizarre nature of the content presents problems. A number of researchers have failed to achieve satisfactory inter-rater reliability only on ratings of bizarreness (Kendler et al. 1983; Flaum et al. 1991; Junginger et al. 1992).

Moor and Tucker (1979) discuss problems with the criteria of falsity and deviance of delusional beliefs. They argue that false beliefs are common, and if having a false belief were a sufficient condition for having a delusion, then many, if not most, people would be delusional. The occurrence of false beliefs, particularly unusual ones, may, they suggest, be taken as a sign of a delusion, but it should not be regarded as a defining condition. The problem with the criterion of deviance is the difficulty of choosing the ‘right’ group as the reference class. They note that a distressing consequence of accepting the deviant belief view is that it helps to legitimize the use of psychiatric treatment for political repression against minorities with dissenting opinions.

More recently Walkup (1990) has argued that some delusional beliefs are not so much false as unfalsifiable, because, like certain religious beliefs, they do not make truth claims, that is factual claims about states of affairs in the world. He proposes that these unfalsifiable delusions are essentially descriptions of subjective experience, although this may not always be immediately obvious. As an example, Walkup gives ‘I didn’t do that’ referring to a patient’s arm movement, witnessed by observers. However, the patient, he argues, may in fact be (correctly) describing his experience of the arm movement as alien.

Spitzer (1990) would, however, argue that Walkup’s classification of ‘unfalsifiable delusions’ are not in fact delusions but rather ‘disorders of experience’, since delusions are, by his account, statements about external reality. We will be returning to the relationship of belief to experience in subsequent chapters.

Spitzer (1990) also cites other difficulties with the criterion of falsity. He suggests that some delusional statements, while they do make truth claims, are unfalsifiable in practice, for example the claim that the patient is being followed by the CIA. Additionally, it has long been recognized that certain delusions may be true, whether coincidentally or as a consequence of the delusion itself: delusions of jealousy may fall into this category.

Mullen (1979), in discussing his definition, asserts that the conditions of absolute conviction and imperviousness do not serve alone to distinguish deluions from normal beliefs and common error. He emphasizes the idiosyncratic nature of the belief’s content when compared with the beliefs of those common to the individual’s social group (i.e. he espouses the deviant belief view). Mullen’s concept of the delusion’s origin is Jasperian: it is ‘to be sought in some as yet little understood disruption and change of mental function which fundamentally alters the patient’s knowledge of the world’ (Mullen 1979, p. 36). Mullen, in common with other writers, notes that a true belief may coincidentally be a delusion; thus the way that the belief emerges and the reasons for its acceptance will determine whether it is classified as a delusion. He also accepts the Jasperian distinction between primary and secondary delusions, in terms of the criterion of being understandable. The primary delusion is ‘an ultimately irreducible phenomena [sic] not amenable to psychological understanding and only explicable finally in terms of the causal connections governing the presumed organic changes in the brain’ (Mullen 1979, p. 38). Mullen ends his discussion with a statement which, like Jaspers’, reflects a view of an unassailable dichotomy between delusions and normal beliefs: ‘Delusion represents a profound and complex disorganisation of mental life stretching way beyond mere false ideas and mistaken beliefs’ (Mullen 1979, p. 40).

Definitions in diagnostic systems, for example the Diagnostic and statistical manual (DSM III-R) (American Psychiatric Association (APA) 1987), also assume a dichotomy between delusions and normal beliefs. The DSM III-R definition states:

Delusion. A false personal belief based on incorrect inference about external reality and firmly sustained in spite of what almost everyone else believes and in spite of what constitutes incontrovertible and obvious proof or evidence to the contrary. The belief is not one ordinarily accepted by other members of the person’s subculture (i.e. it is not an article of religious faith).

The Present State Examination (Wing et al. 1974), unlike the DSM III-R, allows for full delusions and ‘partial delusions’, which, while definitely present, are expressed with doubt, and also preserves the tradition of a primary/secondary distinction.

Dichotomy or dimension?

The notion of a simple presence/absence of a delusion has been questioned for some years. Despite the absolutist language of much that Jaspers wrote, he himself raised the question of whether the delusion is to be comprehended ‘as a break in the normal life-curve or simply as part of the continuum of personality development’ (Jaspers 1913, p. 98). In 1968, Strauss published an influential pape...

Table of contents

• Cover
• Title
• Copyright
• Contents
• List of tables
• List of figures
• 1. Concepts of delusion
• 2. Reasoning, rationality, and delusions
• 3. Studies of reasoning in people with psychosis
• 4. The assessment of delusions
• 5. Characteristics of delusional experience
• 6. Theories of the formation and maintenance of delusions
• 7. Reasoning in people with delusions
• 8. Reasoning about delusions
• 9. Towards a model of delusion formation
• Appendix 1 Reasoning about delusions: a structured interview
• Appendix 2 Notes on reasoning about delusions: a structured interview
• Appendix 3 List of belief statements
• References
• Index