Madness Explained
Page 13
Two subsequent studies have provided broad support for Tien’s findings. Jim van Os and his colleagues conducted psychiatric interviews with over 7000 people randomly selected from the general population of Holland.9 When abnormal experiences secondary to drug-taking or physical illness were excluded, 1.7 per cent were found to have experienced ‘true’ hallucinations, but a further 6.2 per cent had experienced hallucinations that were judged not clinically relevant because they were not associated with distress. Comparable results were obtained in a survey of 761 residents of Dunedin, New Zealand, recently reported by Richie Poulton and others.10
To appreciate the significance of these findings it may help to compare them with the available epidemiological data on schizophrenia. Recent estimates suggest that, in most countries, fewer than 1 per cent of the general population receive a diagnosis of schizophrenia at some point in their lives.11 It now appears that about ten times as many people have experienced hallucinations.
Delusional beliefs
There has been much less research on the prevalence of delusional beliefs, a symptom usually attributed either to schizophrenia, manic depression or paranoia. This is probably because researchers have recognized that distinguishing between delusions and beliefs that are just bizarre or unusual is an inherently uncertain enterprise. A Gallup poll of 1236 American adults revealed that approximately one quarter believed in ghosts.12 A similar proportion reported telepathic experiences, about one in ten claimed to have been in the presence of a ghost, and about one in seven thought they had seen a UFO. In a similar interview study of 502 people from the general population of Winnipeg, Canada, it was found that over 15 per cent claimed to have experienced telepathy and that nearly 18 per cent reported experiencing dreams that predicted future events. In this study, belief in the paranormal was associated with various indices of psychiatric problems, including Schneider’s first-rank symptoms.13 However, other researchers have observed that those reporting paranormal experiences often experience high levels of subjective well-being.14
Psychiatrists have sometimes suggested that spiritual experiences should be regarded as evidence of mental illness15 (an idea that has been supported by the government of the People’s Republic of China, where members of the Falun Gong religious movement have recently been subjected to compulsory psychiatric treatment).16 Although this argument cannot be taken seriously by anyone capable of respecting religious sentiments shared by a large proportion of the world’s population, this does not mean that we should not consider similarities between religious beliefs and the delusional beliefs of patients. That these similarities can be marked is evident from a study reported by Mike Jackson, a psychologist at the University College Bangor in Wales, and Bill Fulford, an Oxford-based psychiatrist and philos-opher.17 Jackson and Fulford carried out a detailed study of three people whose experiences were recorded by the Alistair Hardy Research Centre at Oxford University, which investigates religious experiences. All three reported beliefs that met standard psychiatric definitions of delusions (two also experienced auditory hallucinations). For example, ‘Simon’, a 40-year-old man, was raised as a Baptist and enjoyed a successful career until he fell into a legal dispute with his colleagues. After praying for guidance late at night, he noticed that wax from a candle had dripped on to his Bible, obscuring certain words. Interpreting this event as a message from God, he realized that he was ‘The living son of David… also a relative of Ishmael, and… captain of the guard of Israel’.
British psychiatrist Glen Roberts conducted a study comparing deluded patients, patients who had recovered from delusions, trainee Anglican priests (chosen because of their presumed religious convictions) and ordinary people, finding that both the currently deluded patients and the trainee priests, but not the recovered patients or the ordinary people, expressed an extremely strong need to find meaning in their lives.18 In a more recent study, Emmanuelle Peters and her colleagues at the Institute of Psychiatry in London compared psychotic inpatients and ordinary people to members of new religious movements (Druids and members of the Hare Krishna religion). Although the members of the new religious movements were not ‘ill’ in the sense of wanting or appearing to need treatment, the two groups could not be distinguished on a measure of delusional beliefs.19
A similar controversy has concerned the relationship between psychosis and beliefs about visits to Earth by extraterrestrials. In the United States in recent years, a surprising number of people have reported being kidnapped by aliens. Typically, ‘abductees’ describe being taken from their beds at night. Later they find themselves in a UFO, being inspected by aliens (usually described as ‘greys’ – small humanoid creatures with thin faces and slanting eyes). They are forced to lie helpless as their bodies are probed and penetrated by alien devices, presumably as part of some kind of interplanetary zoology experiment. Eventually, they are returned to their beds unharmed. Estimates of the number of people in the USA who have had ‘abduction experiences’ have been as high as 3.7 million.20 One prominent psychiatrist has concluded that they are honest accounts of real events,21 provoking harsh criticism from his colleagues. Some features of abduction accounts are strikingly reminiscent of the passivity delusions included in Schneider’s list of first-rank symptoms, but whether these kinds of experiences are associated with psychopathology remains a matter of dispute.22 Although an American study failed to find evidence of psychopathology in abductees,23 a recent British study found that belief in UFOs was associated with high scores on questionnaire measures of psychotic thinking.24
It is only very recently that attempts have been made to assess the prevalence in the general population of delusional beliefs defined by psychiatric criteria. In the recent survey of more than 7000 Dutch people conducted by Jim van Os and his colleagues, 3.3 per cent of the sample were found to have ‘true’ delusions and 8.7 per cent had delusions that were not clinically relevant (that is, which were not associated with distress and did not require treatment).25 Higher estimates were obtained in Poulton’s developmental study of the residents of Dunedin, New Zealand, in which 20.1 per cent of the sample were recorded as having delusions by the end point of the study, and 12.6 per cent were judged to be paranoid.26
I am aware of only one study in which an attempt has been made to assess the prevalence of different kinds of delusions. In June 1996, thirty-one family doctors in the Aquitaine region of southwest France asked over 1000 patients attending their clinics to complete a questionnaire measuring twenty-one commonly reported delusional beliefs. Only 11.5 per cent of those approached had attended their doctor because of psychiatric problems. The most common delusional ideas reported were that people were not who they seemed to be (69.3 per cent of those with no history of psychiatric disorder); that the individual had experienced telepathic communication (46.9 per cent); that seemingly innocuous events had double meanings (42.2 per cent); that the individual was being persecuted in some way (25.5 per cent); and that occult forces were at work (23.4 per cent).27
Language and communication disorders
Incoherent speech has often been regarded as an important symptom of psychosis. As we saw in Chapter 2, Bleuler believed that this kind of speech reflected the loosening of associations that he held to be a fundamental feature of schizophrenia. The American psychiatrist Nancy Andreasen has developed a formal method of assessing psychotic speech that has been extensively used in recent research. Anticipating our more detailed discussion of this symptom in a later chapter, for present purposes we need only note that her method requires investigators to score segments of speech for twenty different kinds of abnormality. In a validation study, Andreasen reported ratings of abnormal speech from schizophrenia patients, bipolar patients, patients suffering from unipolar depression and ordinary people. The most surprising discovery was that incoherent speech was more often observed in manic patients than in schizophrenia patients (further evidence that the distinction between these diagnoses is not meaningful). Andreasen also observed tha
t incoherence was, to a lesser degree, a feature of the speech of some depressed patients and even of some of the normal people she examined.28 This finding raises the possibility that incoherent speech, like other symptoms of psychosis, is more frequently observed in non-psychotic individuals than has previously been supposed.
This inference receives some support from an unusual study conducted by David Weeks, a clinical psychologist based in Edinburgh, Scotland. Weeks conducted an investigation of self-styled eccentrics (people who believed that their manner and behaviour made them different from ordinary folk) who responded to advertisements he placed in newspapers.29 Many of those who volunteered to participate had very odd attitudes and behaviour. For example, Norma, a woman who lived in Connecticut, played in a kazoo band, wore a fireman’s outfit in the winter, and held parties in the summer in which she served only canned food and dressed as a member of the British royal family. She believed that it was immoral to throw anything away and had to buy an abandoned opera house to hold all of her possessions. Al, another member of Weeks’ sample, rode around his hometown in Virginia on a device that was half bicycle and half rocking horse, behind which he towed a milk crate mounted on a golf cart.
Weeks used Andreasen’s scale to analyse recorded speech samples collected from his eccentrics. As might be expected of a group that had been so loosely defined, the quality of their speech was highly variable. Over half of the eccentrics showed no evidence of speech disorder whatsoever, whereas others showed evidence of severe communication difficulties. The following is an example:
I have since resolved to actually Sherlock Holmes a manuscript, anticipatory, of many practicing psychiatry, this conjectural profession, none to date have concentrated their probes into the mind’s cognitive faculties, which… I suspect… is… as it were, a high-octane, rather than the typically average petrol… that circumstances, IQ and health, is responsible for neurosis. Is it a key to the wonderful fulfilment of this gift of life? Whiter light needs darker shadow. The greyest gap in psychiatry is that it must accept creative individuals are left to stew in their own portentous juices to work out their eccentricity unaided.30
Weeks was careful not to claim that his eccentrics were psychotic. Indeed, in the case of two categories of abnormal speech – derailment (a pattern of speech in which ideas seem to slip off one track on to another, obliquely related track) and loss of goal (failure to follow a chain of thought to its logical conclusion) – the eccentrics showed less evidence of abnormality than ordinary people. However, for most of the other types of speech disorder, and particularly for pressure of speech (rapid talking that is difficult to interrupt), tangentiality (responding to questions in an oblique or irrelevant manner), and circumstantiality (speech that is delayed in reaching its goal because of the intrusion of many tenuously related ideas), the eccentrics showed more evidence of abnormality than ordinary people.
Of course, just as some kinds of peculiar beliefs may not be related to delusions, so too some kinds of abnormal speech should not be regarded as forms of language and communication disorder. For example, glossolalia, the speaking in unknown tongues practised by some Christian sects, has sometimes been described as similar to the speech of schizophrenia patients,31 but is, in fact, linguistically quite different32 and, unlike the disordered speech of patients, is usually brought on wilfully in specific religious settings.33
So far as I am aware, only one study has reported a population estimate for psychotic speech. In Poulton’s study of people in Dunedin, the speech of the participants was rated by a social worker as they arrived to be assessed, and 17.9 per cent of the sample were rated as having disorganized speech.34
Hypomania
Mood swings, like the other symptoms we have considered, appear to be much more commonly experienced than would be anticipated on the basis of Kraepelin’s paradigm. For example, American psychologist Ronald Depue and his colleagues have estimated from questionnaire studies that 6 per cent of college students show evidence of abnormal variations in mood.35
In the Zurich canton of Switzerland, a team led by psychiatrist Jules Angst interviewed a representative sample of the general population and estimated that 4 per cent had experienced mild episodes of mania (known as hypomania).36 In a later study, in which the sample was followed up over a fourteen-year period, 5.5 per cent had experienced an episode meeting the DSM-IV criteria for hypomania and a further 11.3 per cent had experienced ‘subdiagnostic’ hypomanic symptoms.37
Reviewing similar investigations conducted in several different countries, Hagop Akiskal, a psychiatrist at the University of California at San Diego, concluded that, ‘Softer bipolar expressions are at least 4–6 times more common than the usual prevalence of 1 per cent given for classic manic-depressive illness.’38
From Sanity to Madness
It seems that there is some truth in Bleuler’s view that the differences between sanity and madness are matters of degree. In the 1920s, Ernst Kretschmer, a professor of psychiatry at the University of Tübingen, elaborated Bleuler’s theory, arguing that both schizophrenia and manic depression were related to variations in normal personality.39 According to Kretschmer, there is a type of ‘schizothymic’ personality characterized by a combination of coldness and hypersensitivity. Similarly, he argued that there is a ‘cyclothymic’ personality type that resembles manic depression, in which the individual is prone to extreme moods. Kretschmer believed that these personality types, and the clinical states related to them, were associated with particular bodily constitutions. The schizophrenia patient, on his view, was most likely to be of asthenic build, that is, frail with a narrow physique. The manic-depressive patient, on the other hand, was most likely to have the pyknic build, being middle in height, and rounded, with a tendency towards fat around the trunk. (Although some early studies reported data consistent with Kretschmer’s theory,40 so far as I am aware, these relationships between psychopathology and physical stature have never been verified by modern research.)
The concept of schizotypy
Unfortunately, Kretschmer’s ideas had no immediate impact on psychiatric research (although they did influence some psychologists studying normal variations in personality)41 and it was nearly half a century before the hypothesized continuum between sanity and madness was investigated properly. Modern studies in this area were stimulated by the ideas of American psychologist Paul Meehl, expressed in a 1962 speech he made as president of the American Psychological Association.42 Focusing on schizophrenia, Meehl argued that inconsistent findings from genetic research could be accounted for by supposing that individuals inherit a vulnerability to the disorder rather than the disorder itself. He proposed the term ‘schizotaxia’ to describe this predisposition, and suggested that it might lead the individual to experience ‘cognitive slippage’ (his term for the loosening of associations) and ‘anhedonia’ (an inability to experience pleasure). Meehl argued that the majority of people who suffered from schizotaxia would not develop full-blown schizophrenia, but would instead have schizotypal personality characteristics – for example eccentric beliefs and magical thinking. Such people would only become schizophrenic if exposed to some kind of stress.
Meehl’s arguments later gained some support from the adoption studies carried out in Denmark by Seymour Kety, David Rosenthal and their colleagues (see pp. 77–8 for a brief discussion of these investigations). In these studies very little evidence of full-blown psychotic illness was observed in the biological relatives of adoptees who had been diagnosed as suffering from schizophrenia, a finding which, at first sight, seemed to undermine the genetic theory of schizophrenia. However, Kety and Rosenthal argued that many of these biological relatives showed eccentric personality characteristics, for example unusual beliefs about the supernatural, constricted emotions, suspiciousness and social anxiety. Assuming that such people were suffering from a subclinical variant of schizophrenia, they proposed the new diagnostic category of ‘schizophrenia spectrum disorder’ in order to descri
be these characteristics.43
The work of Kety, Rosenthal and their colleagues preceded the publication of DSM-III. Partly influenced by their observations, the authors of the manual decided to include a multi-axial system in which information in addition to diagnoses would be classified. Whereas clinicians were invited to describe their patients’ psychiatric illnesses using axis 1, axis 2 was to be used to classify disorders of personality. These were defined as ‘enduring patterns of perceiving, relating to, and thinking about the environment and oneself’ and were considered to be distinct from illnesses because they were present throughout adulthood, whereas the illnesses were episodic.
The definitions of the axis-2 disorders were drawn from various sources, including psychoanalysts and theories of normal personality. After some debate, eleven were included. Among these were criteria for ‘schizotypal personality disorder’ devised by Robert Spitzer on the basis of Kety and Rosenthal’s concept of ‘schizophrenia spectrum disorder’. Spitzer also constructed a definition of ‘borderline personality disorder’ from earlier formulations suggested by psychoanalytic authors. This term was used to describe a type of personality characterized by extreme emotional instability, severe problems of self-esteem, self-destructive behaviours and intense and unstable relationships with others.44 The confusing name ‘borderline’ was used because some psychoanalysts had theorized that such people lay on the borderline between psychosis and neurosis. However, it was assumed that borderline patients would not show active psychotic symptoms.