±è´ëÁß¾¾°¡ ÀÚ½ÅÀÇ ÞçîÜÀÌ°í öÑÝÁîÜÀÎ ¿¬ÇÕÁ¦¾ÈÀ» °®°í °¡¼ ÓßÑõÀûÈ ¹æ¾ÈÀÎ ¿¬¹æÁ¦¿Í ¦Áþ±â½ÃÅ°´Â ¹Ù¶÷¿¡ ºÏÇÑÁ¤±ÇÀÇ ÓßÑõ°øÀÛÀÌ ¸ÔÇôµé ¼ö Àִ ȯ°æÀÌ Á¶¼ºµÇ¾ú´Ù. '¿¬ÇÕÁ¦+¿¬¹æÁ¦'¾ÈÀº »ê¼úÀûÀ¸·Î '75%îåûù¹æ¾È'ÀÌ´Ù.
¼ÒÀ§ 6¡¤15 ¼±¾ðÀº ¾Æ·¡ ´Ù¼¸ °¡Áö ¾à¼ÓÀ» ÇßÀ¸³ª ÁöÄÑÁø °ÍÀº ´ëÇѹα¹¿¡´Â ºÒ¸®ÇÏ°í ±èÁ¤ÀÏ¿¡°Ô´Â À¯¸®ÇÑ °Íµé»ÓÀÌ´Ù.
ÅëÀÏÀ» '¿ì¸®¹ÎÁ·³¢¸® ÈûÀ» ÇÕÃļ ÀÚÁÖÀûÀ¸·Î ÇØ°áÇÑ´Ù'´Â ´ë¸ñÀº ±è´ëÁß, ³ë¹«Çö ÁÂÆÄÁ¤±Çù» Ä£ºÏÁÂÀͼ¼·Â¿¡ ÀÇÇؼ ¼±µ¿±¸È£·Î äÅõǾú°í Áý±Ç´çÀÇ »ó´ç¼ö ÀÇ¿øµµ ÀÌ¿¡ È£ÀÀÇÏ°í ÀÖ´Ù. '¿ì¸®¹ÎÁ·³¢¸®'¶ó´Â °ÅÁþ±¸È£°¡ °¡Â¥ ¹ÎÁ·°¨Á¤À» ºÎÃß°Ü ÚãÚ¸-ÚãùÛ ¼±µ¿¿¡ ÀÌ¿ëµÇ°í ÀÖ´Ù.
¼ÒÀ§ ºñÀüÇâÀå±â¼ö ¹®Á¦´Â ºÏÇÑÃø¿¡ À¯¸®ÇÑ ¹æÇâÀ¸·Î ÇØ°áµÇ¾ú´Ù. ±è´ëÁß ´ç½Ã ´ëÅë·ÉÀÌ ÀϺ»ÀÎ ³³Ä¡¹ü ½Å±¤¼ö±îÁö Æ÷ÇÔ½ÃÄÑ 63¸íÀ» ºÏ¼ÛÇØÁÖ¾ú±â ¶§¹®ÀÌ´Ù. ±¹±ºÆ÷·Î¿Í ³³ºÏÀÚ´Â ÇÑ »ç¶÷µµ µ¹·Á ¹ÞÁö ¾Ê¾Ò´Ù.
°¡Àå À§ÇèÇÑ Á¶Ç×ÀÎ 2Á¶ÀÇ ÅëÀϹæÇâ ÇÕÀÇ´Â ±× µÚ Çѱ¹»çȸ¸¦ ¹«ÀåÇØÁ¦½ÃÅ°´Â µ¶¼ÒÁ¶Ç×ÀÌ µÇ¾ú´Ù. ±è´ëÁß¾¾°¡ ÀÚ½ÅÀÇ ÞçîÜÀÌ°í öÑÝÁîÜÀÎ ¿¬ÇÕÁ¦¾ÈÀ» °®°í °¡¼ ÓßÑõÀûÈ ¹æ¾ÈÀÎ ¿¬¹æÁ¦¿Í ¦Áþ±â½ÃÅ°´Â ¹Ù¶÷¿¡ ºÏÇÑÁ¤±ÇÀÇ ÓßÑõ°øÀÛÀÌ ¸ÔÇôµé ¼ö Àִ ȯ°æÀÌ Á¶¼ºµÇ¾ú´Ù. '¿¬ÇÕÁ¦+¿¬¹æÁ¦'¾ÈÀº »ê¼úÀûÀ¸·Î '75%îåûù¹æ¾È'ÀÌ´Ù. µÎ üÁ¦, Áï çýÚª°ú ßæ⩸¦ ¼¯´Â ½ÄÀÇ ÅëÀÏÀ» ÇÏÀÚ´Â °ÍÀÌ´Ù. 75%ÀÇ ¿À¹°°ú 25%ÀÇ »ý¼ö°¡ È¥ÇյǸé ßæâ©Àΰ¡, çýÚªÀΰ¡?
ÀÌ Æ´À» Ÿ°í Ä£ºÏÁÂÀÍ ´ÜüµéÀº îåûù¿Í °°Àº ¶æÀ¸·Î '6¡¤15 ¼±¾ð ½Çõ'À» ºÎ¸£Â¢°í, ¿¬¹æÁ¦ ½ÇÇöÀ» Ã˱¸ÇÏ°í ÀÖ´Ù. °ú°Å¿¡´Â ±¹°¡º¸¾È¹ý¿¡ ÀÇÇÏ¿© ó¹ú¹Þ¾ÒÀ» ÁÖÀåÀ» öÑÝÁ¹Ý¿ª¼¼·ÂµéÀÌ °ø°ø¿¬È÷ ÇÏ°í ´Ù³àµµ °ËÂûÀÌ ¼ÕÀ» ³õ°í ÀÖ´Ù.
±èÁ¤ÀÏÀÇ ¼¿ï ÓÍÛ¾ ¾à¼ÓÀº ÁöÄÑÁöÁö ¾Ê¾Ò´Ù. ¾à¼ÓÀ» ¾î°Üµµ Ç×ÀÇ ÇÑ ¹ø ÇÑ ÀûÀÌ ¾ø´Â ±è´ëÁß¾¾´Â ¶Ç ºÏÇÑÀ» ¹æ¹®ÇÏ°Ú´Ù°í ³ª¼¹´Ù°¡ °ÅÀý´çÇÏ¿´´Ù. ½ÅÇÏ°¡ ¿ÕÀ» ¾ËÇöÇÏ·¯ °¡´Â °Íµµ ¾Æ´Ï°í, ÀÌ·± ±¼¿åÀÌ ÀÖÀ» ¼ö ¾ø´Ù. ±×¸¸ÀÌ ±¼¿åÀ» ´çÇÏ´Â °ÍÀÌ ¾Æ´Ï´Ù. ´ëÇѹα¹À» ²ø°í µé¾î°¡¼ ±èÁ¤ÀÏÀÌ ÆijõÀº ÇÔÁ¤¿¡ ºü¶ß¸®°í ¹ÎÁ·¹Ý¿ªÀÚ¿¡°Ô ±¼Á¾Çϵµ·Ï À¯È¤ÇÑ °ÍÀÌ´Ù. ±è´ëÁß¾¾·Î Çؼ ´ëÇѹα¹Àº Ä¡¿åÀ» ´çÇß´Ù.
6¡¤15 ¼±¾ðÀº ¹Ý¿ª¸éÇãÁõÀÌ µÇ¾ú´Ù. ì°Ù¥ÚÏ ´ëÅë·ÉÀº 6¡¤15 ¼±¾ð È°µ¿°¡¸¦ ¼ö¼®¿¡ ³»Á¤ÇÔÀ¸·Î½á ±è´ëÁßÀÌ ¹ß±ÞÇÑ ¹Ý¿ª¸éÇãÁõÀ» ÃßÀÎÇÏ·Á ÇÑ´Ù.
³²ºÏ °øµ¿¼±¾ð¹® (îïÙþ)
Á¶±¹ÀÇ ÆòÈÀû ÅëÀÏÀ» ¿°¿øÇÏ´Â ¿Â °Ü·¹ÀÇ ¼þ°íÇÑ ¶æ¿¡ µû¶ó ´ëÇѹα¹ ±è´ëÁß ´ëÅë·É°ú Á¶¼±¹ÎÁÖÁÖÀÇÀιΰøȱ¹ ±èÁ¤ÀÏ ±¹¹æÀ§¿øÀåÀº 2000³â 6¿ù 13ÀϺÎÅÍ 6¿ù 15ÀϱîÁö Æò¾ç¿¡¼ ¿ª»çÀûÀÎ »óºÀÀ» ÇÏ¿´À¸¸ç Á¤»óȸ´ãÀ» °¡Á³´Ù.
³²ºÏ Á¤»óµéÀº ºÐ´Ü ¿ª»ç»ó óÀ½À¸·Î ¿¸° À̹ø »óºÀ°ú ȸ´ãÀÌ ¼·Î ÀÌÇظ¦ ÁõÁø½ÃÅ°°í ³²ºÏ°ü°è¸¦ ¹ßÀü½ÃÅ°¸ç ÆòÈÅëÀÏÀ» ½ÇÇöÇÏ´Â µ¥ Áß´ëÇÑ ÀÇÀǸ¦ °¡Áø´Ù°í Æò°¡ÇÏ°í ´ÙÀ½°ú °°ÀÌ ¼±¾ðÇÑ´Ù.
1. ³²°ú ºÏÀº ³ª¶óÀÇ ÅëÀϹ®Á¦¸¦ ±× ÁÖÀÎÀÎ ¿ì¸® ¹ÎÁ·³¢¸® ¼·Î ÈûÀ» ÇÕÃÄ ÀÚÁÖÀûÀ¸·Î ÇØ°áÇØ ³ª°¡±â·Î ÇÏ¿´´Ù.
2. ³²°ú ºÏÀº ³ª¶óÀÇ ÅëÀÏÀ» À§ÇÑ ³²ÃøÀÇ ¿¬ÇÕÁ¦¾È°ú ºÏÃøÀÇ ³·Àº ´Ü°èÀÇ ¿¬¹æÁ¦¾ÈÀÌ ¼·Î °øÅ뼺ÀÌ ÀÖ´Ù°í ÀÎÁ¤ÇÏ°í ¾ÕÀ¸·Î ÀÌ ¹æÇâ¿¡¼ ÅëÀÏÀ» ÁöÇâ½ÃÄÑ ³ª°¡±â·Î ÇÏ¿´´Ù.
3. ³²°ú ºÏÀº ¿ÃÇØ 8¡¤15¿¡ ÁîÀ½ÇÏ¿© Èð¾îÁø °¡Á·, ģô¹æ¹®´ÜÀ» ±³È¯ÇÏ¸ç ºñÀüÇâÀå±â¼ö ¹®Á¦¸¦ ÇØ°áÇÏ´Â µî ÀεµÀû ¹®Á¦¸¦ Á¶¼ÓÈ÷ Ç®¾î ³ª°¡±â·Î ÇÏ¿´´Ù.
4. ³²°ú ºÏÀº °æÁ¦Çù·ÂÀ» ÅëÇÏ¿© ¹ÎÁ·°æÁ¦¸¦ ±ÕÇüÀûÀ¸·Î ¹ßÀü½ÃÅ°°í »çȸ¡¤¹®È¡¤Ã¼À°¡¤º¸°Ç¡¤È¯°æ µî Á¦¹Ý ºÐ¾ßÀÇ Çù·Â°ú ±³·ù¸¦ È°¼ºÈÇÏ¿© ¼·ÎÀÇ ½Å·Ú¸¦ ´ÙÁ® ³ª°¡±â·Î ÇÏ¿´´Ù.
5. ³²°ú ºÏÀº ÀÌ»ó°ú °°Àº ÇÕÀÇ»çÇ×À» Á¶¼ÓÈ÷ ½Çõ¿¡ ¿Å±â±â À§ÇÏ¿© À̸¥ ½ÃÀÏ ¾È¿¡ ´ç±¹ »çÀÌÀÇ ´ëȸ¦ °³ÃÖÇϱâ·Î ÇÏ¿´´Ù.
±è´ëÁß ´ëÅë·ÉÀº ±èÁ¤ÀÏ ±¹¹æÀ§¿øÀåÀÌ ¼¿ïÀ» ¹æ¹®Çϵµ·Ï Á¤ÁßÈ÷ ÃÊûÇÏ¿´À¸¸ç ±èÁ¤ÀÏ ±¹¹æÀ§¿øÀåÀº ¾ÕÀ¸·Î ÀûÀýÇÑ ½Ã±â¿¡ ¼¿ïÀ» ¹æ¹®Çϱâ·Î ÇÏ¿´´Ù.
///////////////////////////////////////////////////////////////
1
Beliefs About Delusions
Vaughan Bell, Peter Halligan and Hadyn Ellis.
Published in The Psychologist
Vol 16 No 8, pages 418-423.
August 2003
Reference as:
Bell, V., Halligan, P.W. & Ellis, H. (2003) Belief about delusions. The Psychologist, 16 (8), 418-
423.
Early in his third month of office, President Reagan was on his way to address a conference when
John Hinckley fired six gun shots at point blank range, wounding the president and three of his
entourage. In the controversial trial that followed, three defence psychiatrists successfully argued
that Hinckley was not guilty, on the grounds that he was suffering from the delusion that the
assassination would cause Jodie Foster, the actress from Taxi Driver (a film which Hinckley was
obsessed with), to fall in love with him. In the same year the award-winning author Philip K.
Dick, whose books have been turned into major Hollywood films, such as Blade Runner, Total
Recall and Minority Report, published one of his last books. The sprawling and eccentric VALIS
is a novel based on delusions resulting from his own psychotic breakdown, which he drew on for
much of his prolific career (see box 1).
From these and many other examples, it would appear that unusual or unlikely beliefs have
significant consequences and continue to captivate the interest of many of us. But to examine
such claims we need to know what is meant by a delusion. How do delusions differ from other
abnormal beliefs? Does the study of delusions provide a productive way of understanding
beliefs?
Box 1: Philip K. Dick
Many novels and short stories by Philip K. Dick contain elements from the
delusions he suffered regarding identity and the nature of reality. Dick described
many bizarre experiences and came to believe that human development was
controlled by an entity called VALIS (Vast Active Living Intelligence System) and
that his perception of Orange County, California was an illusion disguising the fact
that he was really living in firstcentury Rome.There were multiple reasons for
Dick¡¯s bizarre beliefs, given his share of trauma, phobias and drug abuse, but it is
likely that many of the delusions he wrote about stemmed from psychotic episodes
he experienced as a sufferer and as an observer of others.This alone makes his
work of great psychological interest. However, Dick also seems to have some
knowledge of contemporary psychology himself, incorporating as he did the work
of Penfield,Vygotsky and Luria (among others) into his stories.
2
Defining issues
Delusions are one of the most important constructs used by psychiatrists to diagnose patients who
are considered to have lost touch with reality (Maher, 1988). For Jaspers (1963), one of the
founders of modern psychiatry, delusions constituted the ¡®basic characteristic of madness¡¯ despite
being ¡®psychologically irreducible¡¯.
More significantly, the detection of delusions has ¡®enormous implications for diagnosis and
treatment, as well as complex notions concerning responsibility, prediction of behaviour, etc.¡¯
(David, 1999). Yet, as pointed out by many commentators (see Jones, 1999), the clinical usage of
the term delusion and its distinction from other abnormal beliefs involve a host of semantic and
epistemological difficulties. Predominant amongst these is our belief that delusions are (to a large
extent) self evident that is, that they constitute a type of belief that (almost) everyone else would
recognise as pathological. This, however, is more apparent than real, and is not even reflected in
the many different opinions that surround the definition of the construct (Berrios, 1991 Garety &
Hemsley, 1994 Spitzer, 1990). Indeed, David (1999) has suggested ¡®there is no acceptable
(rather than accepted) definition of a delusion¡¯ (p.17).
For most of us, however, these thorny issues of definition can be sidestepped by choosing to
adopt the descriptive and widespread characterisation offered by the American Psychiatric
Association¡¯s Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). This
established psychiatric nosology text considers a delusion to be, first and foremost, a form of
belief: a belief whose acceptance and subsequent behaviour can constitute the grounds for
insanity. But no justification is offered and the statement itself amounts to a belief in delusions.
More explicitly, the standard definition characterises delusions as false, based on an incorrect
inference about external reality and different from what almost everyone else believes (APA,
1994). Other features such as degree of conviction and imperviousness to persuasion do not set
delusions apart from other beliefs (Garety & Hemsley, 1994).
Delusions – An abnormal belief by any other name
Despite differences in emphasis, most definitions consider two criteria to be significant when
establishing a delusion: falsifiability and bizarreness. Simply described, ¡®bizarre delusions are
generally impossible, whereas non-bizarre delusions are generally improbable¡¯ (Sedler, 1995,
p.256). The DSM-IV distinguishes these as follows: a non-bizarre delusion may involve
situations that in principle could occur in real life but are thought (by the psychiatrist) to be
highly improbable and therefore potentially falsifiable a bizarre or fantastic belief, however, is
considered impossible and therefore assumed to be one not normally held by others in the culture
or society.
The problem with each of these definitions lies not with the differential distinction, but with the
absence of agreed operational definitions as to how these criteria are arrived at clinically. The
DSM definition does not specify how one might set about establishing the falseness or
bizarreness of the belief nor how one could know whether the belief was the product of an
impaired inference, such as occurs in paranoid patients, who show a tendency to jump to
conclusions in situations requiring probabalistic reasoning (Bentall, 1994). Here we turn to some
specific problems.
3
Falsifiability Non-bizarre delusions involve situations and events that could occur in real life,
such as believing that one is being followed, infected, poisoned or deceived by another. Therefore
the ¡®falsifiability¡¯ criterion can mean that psychiatrists are often required to make judgements on
claims of marital infidelity, persecution or conspiracy in the workplace (Jones, 1999), where the
available relevant evidence is either limited, cannot be ascertained within the confines of the
consulting room, or lies beyond the forensic capabilities of the clinician. As pointed out by
Young (2000), ¡®many of the beliefs considered to be delusions do not meet these criteria (or are
not tested against them) in practice¡¯ (p.47). This can have some curious consequences (see ¡®The
Martha Mitchell Effect, box 2).
Accordingly, this falsity criterion has been rightly questioned (Spitzer, 1990). Moreover, it is
unclear what level of evidence would be required to consider a belief ¡®incontrovertibly false¡¯ and
whether judgements should be based on the ¡®balance of probabilities¡¯ or the more stringent test of
¡®beyond reasonable doubt¡¯. ¡®Delusional¡¯ beliefs, consequently, may not be false (Heise, 1988) or
even firmly sustained (Myin-Germeys et al., 2001).
Bizarre beliefs The attribution that a delusion is bizarre is typically defined in terms of beliefs
considered not normally held by other members of a person¡¯s culture or society. This, however,
often first involves the psychiatrist¡¯s own evaluation as regards the plausibility of the belief after
which the psychiatrist considers whether it is one typically sustained by the others in the person¡¯s
culture. Although both evaluations may be related, they need not be. If, based on his or her own
beliefs and experience, the psychiatrist considers the belief sufficiently bizarre, then presumably
a diagnosis of delusion can be made independent of ascertaining the actual prevalence of the
belief in the patient¡¯s culture.
The DSM definition, however, clearly assumes that the criterion of abnormality or bizarreness
should be obvious, given that the belief is one not ordinarily accepted by other members of a
Box 2: The Martha Mitchell Effect
Sometimes improbable patient reports are erroneously assumed to be symptoms of
mental illness (Maher, 1988).The ¡®Martha Mitchell effect¡¯ referred to the tendency
of mental health practitioners not to believe the experience of the wife of the
American attorney general, whose persistent reports of corruption in the Nixon
White House were initially dismissed as evidence of delusional thinking, until later
proved correct by the Watergate investigation. Such examples demonstrate that
delusional pathology can often lie in the failure or inability to verify whether the
events have actually taken place, no matter how improbable intuitively they might
appear to the busy clinician. Clearly, there are instances ¡®where people are pursued
by the Mafia¡¯ or are ¡®kept under surveillance by the police¡¯, and where they rightly
suspect ¡®that their spouse is unfaithful¡¯ (Sedler, 1995).As Joseph H. Berke (1998)
wrote, even paranoids have enemies! For understandable and obvious reasons,
however, little effort is invested by clinicians into checking the validity of claims of
persecution or harassment, and without such evidence the patient could be labelled
delusional.
4
person¡¯s culture or subculture. This is not necessarily a reliable strategy: many studies of
psychiatrists show poor interrater reliability for ratings of bizarre beliefs (Flaum et al., 1991
Junginger et al., 1992). Moreover, most clinicians are not in a position to know or find out
whether such beliefs comprise those normally accepted, except by direct comparison with those
of his or her own peer group.
One method of comparison is the use of large-scale surveys, but most clinical judgements on the
prevalence of beliefs in society are not typically informed by empirical evidence. In fact, beliefs
in unscientific or parapsychological phenomena are not statistically uncommon (see Della Salla,
1999), and were this criterion alone employed as a sufficient condition, then many of us at times
might be classified as delusional (Moor & Tucker, 1979). Large-scale marketing research polls
carried out in the UK and North America consistently reveal that significant numbers of people
within society hold strong beliefs about the paranormal. For example, a 1998 UK survey found
that 41 per cent of respondents believed in communication with the dead, and 49 per cent
believed in heaven – but only 28 per cent in hell (¡®Survey of paranormal beliefs¡¯, 1998).
Such surveys also reveal important cultural differences in held beliefs. In many Western
countries opinion polls confirm that large numbers believe in god(s) and hold other paranormal
beliefs (Taylor, 2003). Consequently, religious beliefs, including praying to a deity, are not
typically considered delusional, while believing and claiming that one is a deity (see ¡®The Three
Christs of Ypsilanti¡¯, box 3) or that one¡¯s spouse has been replaced (see ¡®Capgras delusion¡¯, box
4) typically are.
The existence of high levels of conviction in what might be considered abnormal, unscientific or
paranormal beliefs raises important questions for mental health workers when justifying the
notion of bizarre beliefs on purely conceptual or statistical grounds. As pointed out by French
(1992), most beliefs are based upon ¡®personal experiences perhaps supported by reports of trusted
others, and the general cultural acceptance that such phenomena are indeed genuine¡¯.
Although clinically important, the conceptual basis for the criteria of falsification or impossibility
clearly breaks down under scrutiny. It is also problematic because psychotic symptoms such as
delusions and hallucinations are not inevitably associated with the presence of a psychiatric
disorder (Johns & van Os, 2001). Consequently, patients with DSM-IV-type delusions do not
constitute a homogeneous group.
Box 3: The Three Christs Of Ypsilanti
In 1959 social psychologist Milton Rokeach brought together three schizophrenic
patients in the same psychiatric ward in Ypsilanti, Michigan, all of whom suffered
from the Messiah complex – each believed he was Jesus Christ. Rokeach was
interested in seeing whether these mutually exclusive delusions would interact and
affect the extent of conviction and content of each patient¡¯s delusional beliefs. In his
book Rokeach (1964/1981) records how each patient dealt with this conflict, one by
avoidance, one by relinquishing his delusion and the other by attributing the identity
claims of his compatriots to mental illness.Whilst this study would be considered
ethically dubious today, it was one of the most original forays into the study of
psychopathology where the explicit aim was to inform normal belief processes.
5
More often than not the decision about whether or not a belief is delusional is made on pragmatic
grounds – namely, the evidential consequences of the beliefs including the extent of personal
distress, potential or actual injury or social danger generated by the belief. Sometimes the
decision may be simple – Cotard¡¯s delusion, a person¡¯s belief that they are dead, may be assessed
differently from a delusion of grandeur such as believing that you are dating a famous TV star.
Can delusions tell us about ¡®normal¡¯ beliefs?
Notwithstanding difficulties with the standard psychiatric definitions, most people accept that
normal beliefs perform an essential and fundamental process in establishing mental reference
points from which to help explain and interact with the world. It is impossible to understand
racism, prejudice, and political and religious conflict without considering discrepancy in
fundamental belief systems. Fodor (1983) indicated that beliefs comprise a ¡®central¡¯ cognitive
process and should be regarded as qualitatively different from the modular processes that have
been well exploited by cognitive neuropsychologists (Coltheart, 1999). The proposition,
however, is not matched by any clear consensus in neuropsychological accounts of what
constitutes the cognitive or neural mechanisms involved, the evolutionary functions, or how such
beliefs can be changed and maintained.
Jones (1999) describes beliefs as mental forms that incorporate the capacity to influence
behaviour and cognition and govern the way people think and what they do. But the debate as to
what defines a belief or belief state rumbles on, and some researchers have instead opted to
examine the ways in which damage or change to known cognitive processes can affect belief
formation, as communicated or acted upon by patients diagnosed as suffering from delusions.
Bryant (1997) observed that over the past 20 years a variety of cognitive models of belief
formation have drawn ¡®empirical support from evidence that delusions can be elicited in normal
individuals undergoing anomalous experiences (Zimbardo et al., 1981), the prevalence of
delusions in neuropathological disturbances of sensory experience (Ellis & Young, 1990),
reasoning deficits in deluded patients (Garety et al., 1991) and the tendency for deluded patients
to make external attributions following negative life events (Kaney & Bentall, 1989)¡¯ (p.44).
Recent developments from cognitive neuropsychiatry have shown how detailed investigations of
monodelusional conditions (e.g. Capgras) can help to generate testable theories of delusion, face
Box 4: Capgras Delusion
Following a car crash in September 1995 Alan Davies became convinced that his
wife of 31 years died in the accident and had been replaced by someone with whom
he did not want to share his life. Diagnosed as suffering from Capgras syndrome, Mr
Davies was awarded £130,000 damages after it was claimed that his rare psychiatric
syndrome was caused by the crash that he and his wife, Christine, had survived.
Despite suffering only minor physical injury he came to regard his wife, whom he
now called Christine II, as an imposter and became stressed by any show of affection
(de Bruxelles, 1999).
6
recognition and normal belief formation (Ellis & Lewis, 2001). But this potentially rich vein of
research for cognitive neuropsychiatry (see Coltheart and Davis, 2000 Halligan & David, 2001)
does not necessarily imply that delusions are the primary source of psychopathology in patients
diagnosed as psychotic. Since most patients requiring psychiatric help have fully formed
delusions by the time they are clinically diagnosed, establishing the causal factors responsible for
the delusion is difficult. The neuropsychological or neurophysiological abnormalities observed
could just as easily be interpreted as the product rather than the cause of these mental disorders.
However, if the formation of delusions as abnormal beliefs is the product of selective but as yet
unspecified cognitive disturbance (e.g. in reasoning, thinking, attribution) then studying delusions
may inform our understanding of how this psychopathology impacts on normal belief systems.
Either way, they provide a platform for elucidating the cognitive architecture of belief formation
itself.
Future directions from a useful past
Despite the concept of delusion being common parlance in psychiatry and society, it is only in
the last 20 years that serious attempts have been made to define and understand the construct in
formal cognitive terms (Bentall et al., 2001 Coltheart & Davis, 2000 Garety & Hemsley, 1994).
One area that has been either ignored or relegated to a mysterious box in belief formation
diagrams is the influence of our current ¡®web of beliefs¡¯ on the adoption or rejection of new
beliefs. Stone and Young (1997) strongly argued that belief formation may involve weighing up
explanations that are observationally adequate versus those that fit within a person¡¯s current
belief set. However, a plausible process by which beliefs may be integrated into such a belief set,
or by which such a pre-existing set may influence how we generate beliefs about our perceptual
world, has not been widely adopted.
Philosophers and social psychologists have attempted to piece together some of this network –
and with some success. Quine and Ullian (1978) set out some philosophical principles by which a
web of belief should operate. Of particular interest is their principle that beliefs are more easily
shed, adopted or altered when the resulting network disruption is minimal, and that beliefs are
validated by their relationships with existing beliefs. Moreover, they claim that any belief ¡®can be
held unrefuted no matter what, by making enough adjustments in other beliefs¡¯ (p.79) – though
sometimes this results in madness. Based on the idea that not all beliefs (or links) are created
equal empirical work has shown that particular beliefs can be differentiated by the amount and
strength of other beliefs, which are relied on for justification (Maio, 2002).
One theoretical framework that we are exploring in Cardiff is that provided by coherence theory
(Thagard, 2000) when considering dynamic models of belief processes in action. Our working
model describes how active beliefs can be evaluated for their acceptability by how well they
cohere into existing belief sets. Beliefs and the constraints between them (for example, believing
that Elvis is alive would constrain you to reject the belief that he is buried at Graceland) can be
given values or weights. These allow an overall measure of coherence to be calculated and also
permit a quantitative measure of disruption when beliefs are added, discarded or revised.
Sensory input may be a constraint in itself with the threshold for believing things obtained from
your own senses (¡®I believe it was raining this morning¡¯) considered higher than those taken on
authority alone (¡®I believe it was raining during the Battle of Waterloo¡¯). This hierarchy may
partly explain why in some cases delusional beliefs can be adopted over very short periods and
with such conviction, and involve the sufferer dramatically revising other beliefs to cohere with
7
their new-found preoccupation. Unusual experiences, which may accompany brain injury or
mental illness, may also give direct perceptual experience for unlikely or bizarre beliefs that
cause a radical reorganisation of a previously conservative belief network.
However, there must be more to pathological beliefs than simply reacting to unusual experiences,
otherwise our belief systems would be in a constant state of flux. Influences on the ways in which
individuals establish links between beliefs and their subsequent relevance for the individual also
need to be taken into account when trying to explain why delusions are often considered bizarre.
A coherence theory account can address some of these problems by allowing reasoning biases to
be modelled via damage to the constraints between beliefs. Of particular advantage to this
approach is that coherence models can be implemented as artificial neural networks.
This means the model can address predictions from neuropsychiatry. For example, Spitzer (1995)
has argued for the the role of dopamine modulation in perceiving significance. He likens the role
of dopamine to a perceptual ¡®signal to noise ratio¡¯ contrast control, where too little modulation
could mean we make no useful distinction between meaningful and nonmeaningful information.
Too much, however, could lead us to see significance and meaning in perceptual information that
we might otherwise ignore, causing, according to Spitzer, a range of unusual and unlikely beliefs.
Given the heterogeneity and complexity of the factors involved, not least of agreeing a common
language to describe and access the construct of abnormal beliefs in question, it would seem
sensible to adopt an eclectic approach to delusions – one that links understanding from
neuroscience, cognitive and social psychology. This would allow ¡®abnormal¡¯ and delusional
beliefs to be understood as arising not simply from damaged biological mechanisms or
information processing modules, but from cognitive beings firmly situated within their social
milieu. Such an approach might also better allow us to treat patients with distressing beliefs, as
well as provide a clearer insight into how each of us comes to hold our own beliefs, be they
viewed by others as mundane, profound or peculiar.
8
References
American Psychiatric Association (1994). Diagnostic and statistical manual of mental disorders
(4th edn).Washington, DC:Author.
Bentall, R.P., Corcoran, R., Howard, R., Blackwood, N., & Kinderman, P. (2001). Persecutory
delusions:A review and theoretical integration. Clinical Psychology Review, 21, 1143.
Berke, J.H. (1998). Even paranoids have enemies: New perspectives on paranoia and
persecution. London and New York: Routledge.
Berrios, G.E. (1991). Delusions as ¡®wrong beliefs¡¯:A conceptual history. British Journal of
Psychiatry, 14, 6.
Bryant, R.A. (1997). Folie a familie:A cognitive study of delusional beliefs. Psychiatry, 60, 44–
50.
Coltheart, M. (1999). Modularity and cognition. Trends in Cognitive Science, 3(3), 115.
Coltheart, M. & Davis, M. (Eds.) (2000). Pathologies of belief. Oxford: Blackwell.
David,A.S. (1999). On the impossibility of defining delusions. Philosophy, Psychiatry
and Psychology, 6, 17.
de Bruxelles, S. (1999, 5 March). Crash victim thinks wife is an imposter. The Times, p.7.
Della Salla, S. (Ed.) (1999). Mind myths. New York:Wiley.
Ellis, H.D. & Lewis, M.B. (2001). Capgras delusion:A window on face recognition. Trends in
Cognitive Sciences, 5(4),149.
Flaum, M.,Arndt, S. & Andreasen, N.C. (1991).The reliability of ¡®bizarre¡¯ delusions.
Comparative Psychiatry, 32, 59.
Fodor, J. (1983). The modularity of mind. Cambridge, MA: MIT Press.
French, C.C. (1992). Factors underlying belief in the paranormal: Do sheep and goats think
differently? The Psychologist, 5, 295.
Garety, P.A. & Hemsley, D.R. (1994). Delusions: Investigations into the psychology of
delusional reasoning. Oxford: Oxford University Press.
Halligan, P.W. & David,A.S. (2001). Cognitive neuropsychiatry: Towards a scientific
psychopathology. Nature Neuroscience Review, 2, 209.
Heise, D.R. (1988). Delusions and the construction of reality. In T. Oltmanns & B. Maher (Eds)
Delusional beliefs (pp.259) Chichester:Wiley.
9
Jaspers, K. (1963). General psychopathology (7th edn J. Hoenig & M. Hamilton,Trans.).
Manchester: Manchester University Press.
Johns, L.C. & van Os, J. (2001).The continuity of psychotic experiences in the general
population. Clinical Psychology Review, 21, 1125.
Jones, E. (1999).The phenomenology of abnormal belief. Philosophy, Psychiatry and
Psychology, 6, 1.
Junginger, J., Barker, S. & Coe, D. (1992). Mood theme and bizarreness of delusions in
schizophrenia and mood psychosis. Journal of Abnormal Psychology, 101, 287.
Maio, G.R. (2002).Values – Truth and meaning. The Psychologist, 15, 296.
Maher, B. (1988).Anomalous experience and delusional thinking:The logic of explanations. In
T.F. Oltmanns and B.A. Maher (Eds.) Delusional beliefs (pp.15). Chichester:Wiley.
Moor, J.H. & Tucker, G.J. (1979). Delusions:Analysis and criteria. Comprehensive Psychiatry,
20, 388.
Myin-Germeys, I., Nicolson, N.A. & Delespaul, P.A.E.G. (2001).The context of delusional
experiences in the daily life of patients with schizophrenia. Psychological Medicine, 31, 489–
498.
Quine,W.V. & Ullian, J.S. (1978). The web of belief (2nd edn). Toronto: Random House.
Rokeach, M. (1981). The three Christs of Ypsilanti. New York: Columbia University Press.
(Original work published 1964)
Sedler, M.J. (1995). Understanding delusions. The Psychiatric Clinics of North America, 18,
251.
Spitzer,M. (1990). On defining delusion. Comprehensive Psychiatry, 31, 377.
Spitzer,M. (1995).A neurocomputational approach to delusions. Comprehensive Psychiatry, 36,
83.
Survey of paranormal beliefs. (1998, 2 February). Daily Mail.
Thagard, P. (2000). Coherence in thought and action. Cambridge, MA: MIT Press.
Stone,T. & Young,A.W. (1997). Delusions and brain injury:The philosophy and psychology of
belief. Mind and Language, 12, 327.
10
Taylor, H. (2003, 26 February).The religious and other beliefs of Americans 2003. Harris
Interactive. Retrieved 14 Apr 2003 from
www.harrisinteractive.com/harris_poll/index.asp?PID=359
Young, A.W. (2000).Wondrous strange: The neuropsychology of abnormal beliefs. In M.
Coltheart and M. Davis (eds) Pathologies of belief (pp. 47). Oxford: Blackwell.
¼ÒÀ§ 6¡¤15 ¼±¾ðÀº ¾Æ·¡ ´Ù¼¸ °¡Áö ¾à¼ÓÀ» ÇßÀ¸³ª ÁöÄÑÁø °ÍÀº ´ëÇѹα¹¿¡´Â ºÒ¸®ÇÏ°í ±èÁ¤ÀÏ¿¡°Ô´Â À¯¸®ÇÑ °Íµé»ÓÀÌ´Ù.
ÅëÀÏÀ» '¿ì¸®¹ÎÁ·³¢¸® ÈûÀ» ÇÕÃļ ÀÚÁÖÀûÀ¸·Î ÇØ°áÇÑ´Ù'´Â ´ë¸ñÀº ±è´ëÁß, ³ë¹«Çö ÁÂÆÄÁ¤±Çù» Ä£ºÏÁÂÀͼ¼·Â¿¡ ÀÇÇؼ ¼±µ¿±¸È£·Î äÅõǾú°í Áý±Ç´çÀÇ »ó´ç¼ö ÀÇ¿øµµ ÀÌ¿¡ È£ÀÀÇÏ°í ÀÖ´Ù. '¿ì¸®¹ÎÁ·³¢¸®'¶ó´Â °ÅÁþ±¸È£°¡ °¡Â¥ ¹ÎÁ·°¨Á¤À» ºÎÃß°Ü ÚãÚ¸-ÚãùÛ ¼±µ¿¿¡ ÀÌ¿ëµÇ°í ÀÖ´Ù.
¼ÒÀ§ ºñÀüÇâÀå±â¼ö ¹®Á¦´Â ºÏÇÑÃø¿¡ À¯¸®ÇÑ ¹æÇâÀ¸·Î ÇØ°áµÇ¾ú´Ù. ±è´ëÁß ´ç½Ã ´ëÅë·ÉÀÌ ÀϺ»ÀÎ ³³Ä¡¹ü ½Å±¤¼ö±îÁö Æ÷ÇÔ½ÃÄÑ 63¸íÀ» ºÏ¼ÛÇØÁÖ¾ú±â ¶§¹®ÀÌ´Ù. ±¹±ºÆ÷·Î¿Í ³³ºÏÀÚ´Â ÇÑ »ç¶÷µµ µ¹·Á ¹ÞÁö ¾Ê¾Ò´Ù.
°¡Àå À§ÇèÇÑ Á¶Ç×ÀÎ 2Á¶ÀÇ ÅëÀϹæÇâ ÇÕÀÇ´Â ±× µÚ Çѱ¹»çȸ¸¦ ¹«ÀåÇØÁ¦½ÃÅ°´Â µ¶¼ÒÁ¶Ç×ÀÌ µÇ¾ú´Ù. ±è´ëÁß¾¾°¡ ÀÚ½ÅÀÇ ÞçîÜÀÌ°í öÑÝÁîÜÀÎ ¿¬ÇÕÁ¦¾ÈÀ» °®°í °¡¼ ÓßÑõÀûÈ ¹æ¾ÈÀÎ ¿¬¹æÁ¦¿Í ¦Áþ±â½ÃÅ°´Â ¹Ù¶÷¿¡ ºÏÇÑÁ¤±ÇÀÇ ÓßÑõ°øÀÛÀÌ ¸ÔÇôµé ¼ö Àִ ȯ°æÀÌ Á¶¼ºµÇ¾ú´Ù. '¿¬ÇÕÁ¦+¿¬¹æÁ¦'¾ÈÀº »ê¼úÀûÀ¸·Î '75%îåûù¹æ¾È'ÀÌ´Ù. µÎ üÁ¦, Áï çýÚª°ú ßæ⩸¦ ¼¯´Â ½ÄÀÇ ÅëÀÏÀ» ÇÏÀÚ´Â °ÍÀÌ´Ù. 75%ÀÇ ¿À¹°°ú 25%ÀÇ »ý¼ö°¡ È¥ÇյǸé ßæâ©Àΰ¡, çýÚªÀΰ¡?
ÀÌ Æ´À» Ÿ°í Ä£ºÏÁÂÀÍ ´ÜüµéÀº îåûù¿Í °°Àº ¶æÀ¸·Î '6¡¤15 ¼±¾ð ½Çõ'À» ºÎ¸£Â¢°í, ¿¬¹æÁ¦ ½ÇÇöÀ» Ã˱¸ÇÏ°í ÀÖ´Ù. °ú°Å¿¡´Â ±¹°¡º¸¾È¹ý¿¡ ÀÇÇÏ¿© ó¹ú¹Þ¾ÒÀ» ÁÖÀåÀ» öÑÝÁ¹Ý¿ª¼¼·ÂµéÀÌ °ø°ø¿¬È÷ ÇÏ°í ´Ù³àµµ °ËÂûÀÌ ¼ÕÀ» ³õ°í ÀÖ´Ù.
±èÁ¤ÀÏÀÇ ¼¿ï ÓÍÛ¾ ¾à¼ÓÀº ÁöÄÑÁöÁö ¾Ê¾Ò´Ù. ¾à¼ÓÀ» ¾î°Üµµ Ç×ÀÇ ÇÑ ¹ø ÇÑ ÀûÀÌ ¾ø´Â ±è´ëÁß¾¾´Â ¶Ç ºÏÇÑÀ» ¹æ¹®ÇÏ°Ú´Ù°í ³ª¼¹´Ù°¡ °ÅÀý´çÇÏ¿´´Ù. ½ÅÇÏ°¡ ¿ÕÀ» ¾ËÇöÇÏ·¯ °¡´Â °Íµµ ¾Æ´Ï°í, ÀÌ·± ±¼¿åÀÌ ÀÖÀ» ¼ö ¾ø´Ù. ±×¸¸ÀÌ ±¼¿åÀ» ´çÇÏ´Â °ÍÀÌ ¾Æ´Ï´Ù. ´ëÇѹα¹À» ²ø°í µé¾î°¡¼ ±èÁ¤ÀÏÀÌ ÆijõÀº ÇÔÁ¤¿¡ ºü¶ß¸®°í ¹ÎÁ·¹Ý¿ªÀÚ¿¡°Ô ±¼Á¾Çϵµ·Ï À¯È¤ÇÑ °ÍÀÌ´Ù. ±è´ëÁß¾¾·Î Çؼ ´ëÇѹα¹Àº Ä¡¿åÀ» ´çÇß´Ù.
6¡¤15 ¼±¾ðÀº ¹Ý¿ª¸éÇãÁõÀÌ µÇ¾ú´Ù. ì°Ù¥ÚÏ ´ëÅë·ÉÀº 6¡¤15 ¼±¾ð È°µ¿°¡¸¦ ¼ö¼®¿¡ ³»Á¤ÇÔÀ¸·Î½á ±è´ëÁßÀÌ ¹ß±ÞÇÑ ¹Ý¿ª¸éÇãÁõÀ» ÃßÀÎÇÏ·Á ÇÑ´Ù.
³²ºÏ °øµ¿¼±¾ð¹® (îïÙþ)
Á¶±¹ÀÇ ÆòÈÀû ÅëÀÏÀ» ¿°¿øÇÏ´Â ¿Â °Ü·¹ÀÇ ¼þ°íÇÑ ¶æ¿¡ µû¶ó ´ëÇѹα¹ ±è´ëÁß ´ëÅë·É°ú Á¶¼±¹ÎÁÖÁÖÀÇÀιΰøȱ¹ ±èÁ¤ÀÏ ±¹¹æÀ§¿øÀåÀº 2000³â 6¿ù 13ÀϺÎÅÍ 6¿ù 15ÀϱîÁö Æò¾ç¿¡¼ ¿ª»çÀûÀÎ »óºÀÀ» ÇÏ¿´À¸¸ç Á¤»óȸ´ãÀ» °¡Á³´Ù.
³²ºÏ Á¤»óµéÀº ºÐ´Ü ¿ª»ç»ó óÀ½À¸·Î ¿¸° À̹ø »óºÀ°ú ȸ´ãÀÌ ¼·Î ÀÌÇظ¦ ÁõÁø½ÃÅ°°í ³²ºÏ°ü°è¸¦ ¹ßÀü½ÃÅ°¸ç ÆòÈÅëÀÏÀ» ½ÇÇöÇÏ´Â µ¥ Áß´ëÇÑ ÀÇÀǸ¦ °¡Áø´Ù°í Æò°¡ÇÏ°í ´ÙÀ½°ú °°ÀÌ ¼±¾ðÇÑ´Ù.
1. ³²°ú ºÏÀº ³ª¶óÀÇ ÅëÀϹ®Á¦¸¦ ±× ÁÖÀÎÀÎ ¿ì¸® ¹ÎÁ·³¢¸® ¼·Î ÈûÀ» ÇÕÃÄ ÀÚÁÖÀûÀ¸·Î ÇØ°áÇØ ³ª°¡±â·Î ÇÏ¿´´Ù.
2. ³²°ú ºÏÀº ³ª¶óÀÇ ÅëÀÏÀ» À§ÇÑ ³²ÃøÀÇ ¿¬ÇÕÁ¦¾È°ú ºÏÃøÀÇ ³·Àº ´Ü°èÀÇ ¿¬¹æÁ¦¾ÈÀÌ ¼·Î °øÅ뼺ÀÌ ÀÖ´Ù°í ÀÎÁ¤ÇÏ°í ¾ÕÀ¸·Î ÀÌ ¹æÇâ¿¡¼ ÅëÀÏÀ» ÁöÇâ½ÃÄÑ ³ª°¡±â·Î ÇÏ¿´´Ù.
3. ³²°ú ºÏÀº ¿ÃÇØ 8¡¤15¿¡ ÁîÀ½ÇÏ¿© Èð¾îÁø °¡Á·, ģô¹æ¹®´ÜÀ» ±³È¯ÇÏ¸ç ºñÀüÇâÀå±â¼ö ¹®Á¦¸¦ ÇØ°áÇÏ´Â µî ÀεµÀû ¹®Á¦¸¦ Á¶¼ÓÈ÷ Ç®¾î ³ª°¡±â·Î ÇÏ¿´´Ù.
4. ³²°ú ºÏÀº °æÁ¦Çù·ÂÀ» ÅëÇÏ¿© ¹ÎÁ·°æÁ¦¸¦ ±ÕÇüÀûÀ¸·Î ¹ßÀü½ÃÅ°°í »çȸ¡¤¹®È¡¤Ã¼À°¡¤º¸°Ç¡¤È¯°æ µî Á¦¹Ý ºÐ¾ßÀÇ Çù·Â°ú ±³·ù¸¦ È°¼ºÈÇÏ¿© ¼·ÎÀÇ ½Å·Ú¸¦ ´ÙÁ® ³ª°¡±â·Î ÇÏ¿´´Ù.
5. ³²°ú ºÏÀº ÀÌ»ó°ú °°Àº ÇÕÀÇ»çÇ×À» Á¶¼ÓÈ÷ ½Çõ¿¡ ¿Å±â±â À§ÇÏ¿© À̸¥ ½ÃÀÏ ¾È¿¡ ´ç±¹ »çÀÌÀÇ ´ëȸ¦ °³ÃÖÇϱâ·Î ÇÏ¿´´Ù.
±è´ëÁß ´ëÅë·ÉÀº ±èÁ¤ÀÏ ±¹¹æÀ§¿øÀåÀÌ ¼¿ïÀ» ¹æ¹®Çϵµ·Ï Á¤ÁßÈ÷ ÃÊûÇÏ¿´À¸¸ç ±èÁ¤ÀÏ ±¹¹æÀ§¿øÀåÀº ¾ÕÀ¸·Î ÀûÀýÇÑ ½Ã±â¿¡ ¼¿ïÀ» ¹æ¹®Çϱâ·Î ÇÏ¿´´Ù.
///////////////////////////////////////////////////////////////
1
Beliefs About Delusions
Vaughan Bell, Peter Halligan and Hadyn Ellis.
Published in The Psychologist
Vol 16 No 8, pages 418-423.
August 2003
Reference as:
Bell, V., Halligan, P.W. & Ellis, H. (2003) Belief about delusions. The Psychologist, 16 (8), 418-
423.
Early in his third month of office, President Reagan was on his way to address a conference when
John Hinckley fired six gun shots at point blank range, wounding the president and three of his
entourage. In the controversial trial that followed, three defence psychiatrists successfully argued
that Hinckley was not guilty, on the grounds that he was suffering from the delusion that the
assassination would cause Jodie Foster, the actress from Taxi Driver (a film which Hinckley was
obsessed with), to fall in love with him. In the same year the award-winning author Philip K.
Dick, whose books have been turned into major Hollywood films, such as Blade Runner, Total
Recall and Minority Report, published one of his last books. The sprawling and eccentric VALIS
is a novel based on delusions resulting from his own psychotic breakdown, which he drew on for
much of his prolific career (see box 1).
From these and many other examples, it would appear that unusual or unlikely beliefs have
significant consequences and continue to captivate the interest of many of us. But to examine
such claims we need to know what is meant by a delusion. How do delusions differ from other
abnormal beliefs? Does the study of delusions provide a productive way of understanding
beliefs?
Box 1: Philip K. Dick
Many novels and short stories by Philip K. Dick contain elements from the
delusions he suffered regarding identity and the nature of reality. Dick described
many bizarre experiences and came to believe that human development was
controlled by an entity called VALIS (Vast Active Living Intelligence System) and
that his perception of Orange County, California was an illusion disguising the fact
that he was really living in firstcentury Rome.There were multiple reasons for
Dick¡¯s bizarre beliefs, given his share of trauma, phobias and drug abuse, but it is
likely that many of the delusions he wrote about stemmed from psychotic episodes
he experienced as a sufferer and as an observer of others.This alone makes his
work of great psychological interest. However, Dick also seems to have some
knowledge of contemporary psychology himself, incorporating as he did the work
of Penfield,Vygotsky and Luria (among others) into his stories.
2
Defining issues
Delusions are one of the most important constructs used by psychiatrists to diagnose patients who
are considered to have lost touch with reality (Maher, 1988). For Jaspers (1963), one of the
founders of modern psychiatry, delusions constituted the ¡®basic characteristic of madness¡¯ despite
being ¡®psychologically irreducible¡¯.
More significantly, the detection of delusions has ¡®enormous implications for diagnosis and
treatment, as well as complex notions concerning responsibility, prediction of behaviour, etc.¡¯
(David, 1999). Yet, as pointed out by many commentators (see Jones, 1999), the clinical usage of
the term delusion and its distinction from other abnormal beliefs involve a host of semantic and
epistemological difficulties. Predominant amongst these is our belief that delusions are (to a large
extent) self evident that is, that they constitute a type of belief that (almost) everyone else would
recognise as pathological. This, however, is more apparent than real, and is not even reflected in
the many different opinions that surround the definition of the construct (Berrios, 1991 Garety &
Hemsley, 1994 Spitzer, 1990). Indeed, David (1999) has suggested ¡®there is no acceptable
(rather than accepted) definition of a delusion¡¯ (p.17).
For most of us, however, these thorny issues of definition can be sidestepped by choosing to
adopt the descriptive and widespread characterisation offered by the American Psychiatric
Association¡¯s Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). This
established psychiatric nosology text considers a delusion to be, first and foremost, a form of
belief: a belief whose acceptance and subsequent behaviour can constitute the grounds for
insanity. But no justification is offered and the statement itself amounts to a belief in delusions.
More explicitly, the standard definition characterises delusions as false, based on an incorrect
inference about external reality and different from what almost everyone else believes (APA,
1994). Other features such as degree of conviction and imperviousness to persuasion do not set
delusions apart from other beliefs (Garety & Hemsley, 1994).
Delusions – An abnormal belief by any other name
Despite differences in emphasis, most definitions consider two criteria to be significant when
establishing a delusion: falsifiability and bizarreness. Simply described, ¡®bizarre delusions are
generally impossible, whereas non-bizarre delusions are generally improbable¡¯ (Sedler, 1995,
p.256). The DSM-IV distinguishes these as follows: a non-bizarre delusion may involve
situations that in principle could occur in real life but are thought (by the psychiatrist) to be
highly improbable and therefore potentially falsifiable a bizarre or fantastic belief, however, is
considered impossible and therefore assumed to be one not normally held by others in the culture
or society.
The problem with each of these definitions lies not with the differential distinction, but with the
absence of agreed operational definitions as to how these criteria are arrived at clinically. The
DSM definition does not specify how one might set about establishing the falseness or
bizarreness of the belief nor how one could know whether the belief was the product of an
impaired inference, such as occurs in paranoid patients, who show a tendency to jump to
conclusions in situations requiring probabalistic reasoning (Bentall, 1994). Here we turn to some
specific problems.
3
Falsifiability Non-bizarre delusions involve situations and events that could occur in real life,
such as believing that one is being followed, infected, poisoned or deceived by another. Therefore
the ¡®falsifiability¡¯ criterion can mean that psychiatrists are often required to make judgements on
claims of marital infidelity, persecution or conspiracy in the workplace (Jones, 1999), where the
available relevant evidence is either limited, cannot be ascertained within the confines of the
consulting room, or lies beyond the forensic capabilities of the clinician. As pointed out by
Young (2000), ¡®many of the beliefs considered to be delusions do not meet these criteria (or are
not tested against them) in practice¡¯ (p.47). This can have some curious consequences (see ¡®The
Martha Mitchell Effect, box 2).
Accordingly, this falsity criterion has been rightly questioned (Spitzer, 1990). Moreover, it is
unclear what level of evidence would be required to consider a belief ¡®incontrovertibly false¡¯ and
whether judgements should be based on the ¡®balance of probabilities¡¯ or the more stringent test of
¡®beyond reasonable doubt¡¯. ¡®Delusional¡¯ beliefs, consequently, may not be false (Heise, 1988) or
even firmly sustained (Myin-Germeys et al., 2001).
Bizarre beliefs The attribution that a delusion is bizarre is typically defined in terms of beliefs
considered not normally held by other members of a person¡¯s culture or society. This, however,
often first involves the psychiatrist¡¯s own evaluation as regards the plausibility of the belief after
which the psychiatrist considers whether it is one typically sustained by the others in the person¡¯s
culture. Although both evaluations may be related, they need not be. If, based on his or her own
beliefs and experience, the psychiatrist considers the belief sufficiently bizarre, then presumably
a diagnosis of delusion can be made independent of ascertaining the actual prevalence of the
belief in the patient¡¯s culture.
The DSM definition, however, clearly assumes that the criterion of abnormality or bizarreness
should be obvious, given that the belief is one not ordinarily accepted by other members of a
Box 2: The Martha Mitchell Effect
Sometimes improbable patient reports are erroneously assumed to be symptoms of
mental illness (Maher, 1988).The ¡®Martha Mitchell effect¡¯ referred to the tendency
of mental health practitioners not to believe the experience of the wife of the
American attorney general, whose persistent reports of corruption in the Nixon
White House were initially dismissed as evidence of delusional thinking, until later
proved correct by the Watergate investigation. Such examples demonstrate that
delusional pathology can often lie in the failure or inability to verify whether the
events have actually taken place, no matter how improbable intuitively they might
appear to the busy clinician. Clearly, there are instances ¡®where people are pursued
by the Mafia¡¯ or are ¡®kept under surveillance by the police¡¯, and where they rightly
suspect ¡®that their spouse is unfaithful¡¯ (Sedler, 1995).As Joseph H. Berke (1998)
wrote, even paranoids have enemies! For understandable and obvious reasons,
however, little effort is invested by clinicians into checking the validity of claims of
persecution or harassment, and without such evidence the patient could be labelled
delusional.
4
person¡¯s culture or subculture. This is not necessarily a reliable strategy: many studies of
psychiatrists show poor interrater reliability for ratings of bizarre beliefs (Flaum et al., 1991
Junginger et al., 1992). Moreover, most clinicians are not in a position to know or find out
whether such beliefs comprise those normally accepted, except by direct comparison with those
of his or her own peer group.
One method of comparison is the use of large-scale surveys, but most clinical judgements on the
prevalence of beliefs in society are not typically informed by empirical evidence. In fact, beliefs
in unscientific or parapsychological phenomena are not statistically uncommon (see Della Salla,
1999), and were this criterion alone employed as a sufficient condition, then many of us at times
might be classified as delusional (Moor & Tucker, 1979). Large-scale marketing research polls
carried out in the UK and North America consistently reveal that significant numbers of people
within society hold strong beliefs about the paranormal. For example, a 1998 UK survey found
that 41 per cent of respondents believed in communication with the dead, and 49 per cent
believed in heaven – but only 28 per cent in hell (¡®Survey of paranormal beliefs¡¯, 1998).
Such surveys also reveal important cultural differences in held beliefs. In many Western
countries opinion polls confirm that large numbers believe in god(s) and hold other paranormal
beliefs (Taylor, 2003). Consequently, religious beliefs, including praying to a deity, are not
typically considered delusional, while believing and claiming that one is a deity (see ¡®The Three
Christs of Ypsilanti¡¯, box 3) or that one¡¯s spouse has been replaced (see ¡®Capgras delusion¡¯, box
4) typically are.
The existence of high levels of conviction in what might be considered abnormal, unscientific or
paranormal beliefs raises important questions for mental health workers when justifying the
notion of bizarre beliefs on purely conceptual or statistical grounds. As pointed out by French
(1992), most beliefs are based upon ¡®personal experiences perhaps supported by reports of trusted
others, and the general cultural acceptance that such phenomena are indeed genuine¡¯.
Although clinically important, the conceptual basis for the criteria of falsification or impossibility
clearly breaks down under scrutiny. It is also problematic because psychotic symptoms such as
delusions and hallucinations are not inevitably associated with the presence of a psychiatric
disorder (Johns & van Os, 2001). Consequently, patients with DSM-IV-type delusions do not
constitute a homogeneous group.
Box 3: The Three Christs Of Ypsilanti
In 1959 social psychologist Milton Rokeach brought together three schizophrenic
patients in the same psychiatric ward in Ypsilanti, Michigan, all of whom suffered
from the Messiah complex – each believed he was Jesus Christ. Rokeach was
interested in seeing whether these mutually exclusive delusions would interact and
affect the extent of conviction and content of each patient¡¯s delusional beliefs. In his
book Rokeach (1964/1981) records how each patient dealt with this conflict, one by
avoidance, one by relinquishing his delusion and the other by attributing the identity
claims of his compatriots to mental illness.Whilst this study would be considered
ethically dubious today, it was one of the most original forays into the study of
psychopathology where the explicit aim was to inform normal belief processes.
5
More often than not the decision about whether or not a belief is delusional is made on pragmatic
grounds – namely, the evidential consequences of the beliefs including the extent of personal
distress, potential or actual injury or social danger generated by the belief. Sometimes the
decision may be simple – Cotard¡¯s delusion, a person¡¯s belief that they are dead, may be assessed
differently from a delusion of grandeur such as believing that you are dating a famous TV star.
Can delusions tell us about ¡®normal¡¯ beliefs?
Notwithstanding difficulties with the standard psychiatric definitions, most people accept that
normal beliefs perform an essential and fundamental process in establishing mental reference
points from which to help explain and interact with the world. It is impossible to understand
racism, prejudice, and political and religious conflict without considering discrepancy in
fundamental belief systems. Fodor (1983) indicated that beliefs comprise a ¡®central¡¯ cognitive
process and should be regarded as qualitatively different from the modular processes that have
been well exploited by cognitive neuropsychologists (Coltheart, 1999). The proposition,
however, is not matched by any clear consensus in neuropsychological accounts of what
constitutes the cognitive or neural mechanisms involved, the evolutionary functions, or how such
beliefs can be changed and maintained.
Jones (1999) describes beliefs as mental forms that incorporate the capacity to influence
behaviour and cognition and govern the way people think and what they do. But the debate as to
what defines a belief or belief state rumbles on, and some researchers have instead opted to
examine the ways in which damage or change to known cognitive processes can affect belief
formation, as communicated or acted upon by patients diagnosed as suffering from delusions.
Bryant (1997) observed that over the past 20 years a variety of cognitive models of belief
formation have drawn ¡®empirical support from evidence that delusions can be elicited in normal
individuals undergoing anomalous experiences (Zimbardo et al., 1981), the prevalence of
delusions in neuropathological disturbances of sensory experience (Ellis & Young, 1990),
reasoning deficits in deluded patients (Garety et al., 1991) and the tendency for deluded patients
to make external attributions following negative life events (Kaney & Bentall, 1989)¡¯ (p.44).
Recent developments from cognitive neuropsychiatry have shown how detailed investigations of
monodelusional conditions (e.g. Capgras) can help to generate testable theories of delusion, face
Box 4: Capgras Delusion
Following a car crash in September 1995 Alan Davies became convinced that his
wife of 31 years died in the accident and had been replaced by someone with whom
he did not want to share his life. Diagnosed as suffering from Capgras syndrome, Mr
Davies was awarded £130,000 damages after it was claimed that his rare psychiatric
syndrome was caused by the crash that he and his wife, Christine, had survived.
Despite suffering only minor physical injury he came to regard his wife, whom he
now called Christine II, as an imposter and became stressed by any show of affection
(de Bruxelles, 1999).
6
recognition and normal belief formation (Ellis & Lewis, 2001). But this potentially rich vein of
research for cognitive neuropsychiatry (see Coltheart and Davis, 2000 Halligan & David, 2001)
does not necessarily imply that delusions are the primary source of psychopathology in patients
diagnosed as psychotic. Since most patients requiring psychiatric help have fully formed
delusions by the time they are clinically diagnosed, establishing the causal factors responsible for
the delusion is difficult. The neuropsychological or neurophysiological abnormalities observed
could just as easily be interpreted as the product rather than the cause of these mental disorders.
However, if the formation of delusions as abnormal beliefs is the product of selective but as yet
unspecified cognitive disturbance (e.g. in reasoning, thinking, attribution) then studying delusions
may inform our understanding of how this psychopathology impacts on normal belief systems.
Either way, they provide a platform for elucidating the cognitive architecture of belief formation
itself.
Future directions from a useful past
Despite the concept of delusion being common parlance in psychiatry and society, it is only in
the last 20 years that serious attempts have been made to define and understand the construct in
formal cognitive terms (Bentall et al., 2001 Coltheart & Davis, 2000 Garety & Hemsley, 1994).
One area that has been either ignored or relegated to a mysterious box in belief formation
diagrams is the influence of our current ¡®web of beliefs¡¯ on the adoption or rejection of new
beliefs. Stone and Young (1997) strongly argued that belief formation may involve weighing up
explanations that are observationally adequate versus those that fit within a person¡¯s current
belief set. However, a plausible process by which beliefs may be integrated into such a belief set,
or by which such a pre-existing set may influence how we generate beliefs about our perceptual
world, has not been widely adopted.
Philosophers and social psychologists have attempted to piece together some of this network –
and with some success. Quine and Ullian (1978) set out some philosophical principles by which a
web of belief should operate. Of particular interest is their principle that beliefs are more easily
shed, adopted or altered when the resulting network disruption is minimal, and that beliefs are
validated by their relationships with existing beliefs. Moreover, they claim that any belief ¡®can be
held unrefuted no matter what, by making enough adjustments in other beliefs¡¯ (p.79) – though
sometimes this results in madness. Based on the idea that not all beliefs (or links) are created
equal empirical work has shown that particular beliefs can be differentiated by the amount and
strength of other beliefs, which are relied on for justification (Maio, 2002).
One theoretical framework that we are exploring in Cardiff is that provided by coherence theory
(Thagard, 2000) when considering dynamic models of belief processes in action. Our working
model describes how active beliefs can be evaluated for their acceptability by how well they
cohere into existing belief sets. Beliefs and the constraints between them (for example, believing
that Elvis is alive would constrain you to reject the belief that he is buried at Graceland) can be
given values or weights. These allow an overall measure of coherence to be calculated and also
permit a quantitative measure of disruption when beliefs are added, discarded or revised.
Sensory input may be a constraint in itself with the threshold for believing things obtained from
your own senses (¡®I believe it was raining this morning¡¯) considered higher than those taken on
authority alone (¡®I believe it was raining during the Battle of Waterloo¡¯). This hierarchy may
partly explain why in some cases delusional beliefs can be adopted over very short periods and
with such conviction, and involve the sufferer dramatically revising other beliefs to cohere with
7
their new-found preoccupation. Unusual experiences, which may accompany brain injury or
mental illness, may also give direct perceptual experience for unlikely or bizarre beliefs that
cause a radical reorganisation of a previously conservative belief network.
However, there must be more to pathological beliefs than simply reacting to unusual experiences,
otherwise our belief systems would be in a constant state of flux. Influences on the ways in which
individuals establish links between beliefs and their subsequent relevance for the individual also
need to be taken into account when trying to explain why delusions are often considered bizarre.
A coherence theory account can address some of these problems by allowing reasoning biases to
be modelled via damage to the constraints between beliefs. Of particular advantage to this
approach is that coherence models can be implemented as artificial neural networks.
This means the model can address predictions from neuropsychiatry. For example, Spitzer (1995)
has argued for the the role of dopamine modulation in perceiving significance. He likens the role
of dopamine to a perceptual ¡®signal to noise ratio¡¯ contrast control, where too little modulation
could mean we make no useful distinction between meaningful and nonmeaningful information.
Too much, however, could lead us to see significance and meaning in perceptual information that
we might otherwise ignore, causing, according to Spitzer, a range of unusual and unlikely beliefs.
Given the heterogeneity and complexity of the factors involved, not least of agreeing a common
language to describe and access the construct of abnormal beliefs in question, it would seem
sensible to adopt an eclectic approach to delusions – one that links understanding from
neuroscience, cognitive and social psychology. This would allow ¡®abnormal¡¯ and delusional
beliefs to be understood as arising not simply from damaged biological mechanisms or
information processing modules, but from cognitive beings firmly situated within their social
milieu. Such an approach might also better allow us to treat patients with distressing beliefs, as
well as provide a clearer insight into how each of us comes to hold our own beliefs, be they
viewed by others as mundane, profound or peculiar.
8
References
American Psychiatric Association (1994). Diagnostic and statistical manual of mental disorders
(4th edn).Washington, DC:Author.
Bentall, R.P., Corcoran, R., Howard, R., Blackwood, N., & Kinderman, P. (2001). Persecutory
delusions:A review and theoretical integration. Clinical Psychology Review, 21, 1143.
Berke, J.H. (1998). Even paranoids have enemies: New perspectives on paranoia and
persecution. London and New York: Routledge.
Berrios, G.E. (1991). Delusions as ¡®wrong beliefs¡¯:A conceptual history. British Journal of
Psychiatry, 14, 6.
Bryant, R.A. (1997). Folie a familie:A cognitive study of delusional beliefs. Psychiatry, 60, 44–
50.
Coltheart, M. (1999). Modularity and cognition. Trends in Cognitive Science, 3(3), 115.
Coltheart, M. & Davis, M. (Eds.) (2000). Pathologies of belief. Oxford: Blackwell.
David,A.S. (1999). On the impossibility of defining delusions. Philosophy, Psychiatry
and Psychology, 6, 17.
de Bruxelles, S. (1999, 5 March). Crash victim thinks wife is an imposter. The Times, p.7.
Della Salla, S. (Ed.) (1999). Mind myths. New York:Wiley.
Ellis, H.D. & Lewis, M.B. (2001). Capgras delusion:A window on face recognition. Trends in
Cognitive Sciences, 5(4),149.
Flaum, M.,Arndt, S. & Andreasen, N.C. (1991).The reliability of ¡®bizarre¡¯ delusions.
Comparative Psychiatry, 32, 59.
Fodor, J. (1983). The modularity of mind. Cambridge, MA: MIT Press.
French, C.C. (1992). Factors underlying belief in the paranormal: Do sheep and goats think
differently? The Psychologist, 5, 295.
Garety, P.A. & Hemsley, D.R. (1994). Delusions: Investigations into the psychology of
delusional reasoning. Oxford: Oxford University Press.
Halligan, P.W. & David,A.S. (2001). Cognitive neuropsychiatry: Towards a scientific
psychopathology. Nature Neuroscience Review, 2, 209.
Heise, D.R. (1988). Delusions and the construction of reality. In T. Oltmanns & B. Maher (Eds)
Delusional beliefs (pp.259) Chichester:Wiley.
9
Jaspers, K. (1963). General psychopathology (7th edn J. Hoenig & M. Hamilton,Trans.).
Manchester: Manchester University Press.
Johns, L.C. & van Os, J. (2001).The continuity of psychotic experiences in the general
population. Clinical Psychology Review, 21, 1125.
Jones, E. (1999).The phenomenology of abnormal belief. Philosophy, Psychiatry and
Psychology, 6, 1.
Junginger, J., Barker, S. & Coe, D. (1992). Mood theme and bizarreness of delusions in
schizophrenia and mood psychosis. Journal of Abnormal Psychology, 101, 287.
Maio, G.R. (2002).Values – Truth and meaning. The Psychologist, 15, 296.
Maher, B. (1988).Anomalous experience and delusional thinking:The logic of explanations. In
T.F. Oltmanns and B.A. Maher (Eds.) Delusional beliefs (pp.15). Chichester:Wiley.
Moor, J.H. & Tucker, G.J. (1979). Delusions:Analysis and criteria. Comprehensive Psychiatry,
20, 388.
Myin-Germeys, I., Nicolson, N.A. & Delespaul, P.A.E.G. (2001).The context of delusional
experiences in the daily life of patients with schizophrenia. Psychological Medicine, 31, 489–
498.
Quine,W.V. & Ullian, J.S. (1978). The web of belief (2nd edn). Toronto: Random House.
Rokeach, M. (1981). The three Christs of Ypsilanti. New York: Columbia University Press.
(Original work published 1964)
Sedler, M.J. (1995). Understanding delusions. The Psychiatric Clinics of North America, 18,
251.
Spitzer,M. (1990). On defining delusion. Comprehensive Psychiatry, 31, 377.
Spitzer,M. (1995).A neurocomputational approach to delusions. Comprehensive Psychiatry, 36,
83.
Survey of paranormal beliefs. (1998, 2 February). Daily Mail.
Thagard, P. (2000). Coherence in thought and action. Cambridge, MA: MIT Press.
Stone,T. & Young,A.W. (1997). Delusions and brain injury:The philosophy and psychology of
belief. Mind and Language, 12, 327.
10
Taylor, H. (2003, 26 February).The religious and other beliefs of Americans 2003. Harris
Interactive. Retrieved 14 Apr 2003 from
www.harrisinteractive.com/harris_poll/index.asp?PID=359
Young, A.W. (2000).Wondrous strange: The neuropsychology of abnormal beliefs. In M.
Coltheart and M. Davis (eds) Pathologies of belief (pp. 47). Oxford: Blackwell.
Copyright ¨Ï Á¶°©Á¦´åÄÄ - ¹«´ÜÀüÀç ¹× Àç¹èÆ÷ ±ÝÁö
ÇÑ´«¿¡ º¸´Â
º£½ºÆ® ±â»ç
- 1 »ç¶÷ÀÌ ¹ÌÄ¡Áö ¾Ê°í¼¾ß ÀÌ·± ÁþÀº ¸øÇÑ´Ù!
- 2 Çѵ¿ÈÆ°ú ÀÌÁؼ®ÀÇ °æÀï°ú Çù·Â
- 3 À±¼®¿ÀÇ °¡Àå Å« À߸øÀº ¸ñ¼ûÀ» °É¾î¾ß ÇÒ »ç°Ç¿¡ ¸ñ¼ûÀ» °ÉÁö ¾ÊÀº °Í
- 4 Çѵ¿ÈÆ, »çÅðÇÏ¸é¼ 'ºñ¼ö'¸¦ ²È¾Ò´Ù!
- 5 µµÀúÈ÷ ¿ë¼°¡ ¾ÈµÇ´Â À±¼®¿ÀÇ °ÅÁþ¸»!
- 6 °¡Àå ºñ°ÌÇÑ ¸» "ÀÌÀç¸íÀÌ ´ëÅë·ÉÀÌ µÇ¾îµµ ÁÁ´Ù´Â ¸»À̳Ä"
- 7 Á¶¼±ÀϺ¸ ÁÖÇÊ, ±è°ÇÈñ ÁöÅ°·Á°í ºñ»ó°è¾ö·É ÆñÀ» °¡´É¼º Á¦±â!
- 8 "³» ¹ÌÄ£ ÁþÀ¸·Î ¿©·¯ »ç¶÷µé ÀλýÀ» ¸ÁÃÆ´Ù"¶ó°í ÇØ¾ß ÇÒ »ç¶÷ÀÌ!
- 9 ºÎÁ¤¼±°Å À½¸ð·ÐÀÌ ¸Á»óÀÓÀ» °£´ÜÈ÷ Áõ¸íÇÑ´Ù
- 10 Âü ½Î°¡Áö ¾ø´Â À±¼®¿ÀÇ Óß±¹¹Î´ãȹ®