[1] I owe the suggestion to include the bilateral/unilateral distinction related to hallucinations in all modalities to Peter Brugger.
On the Plausibility of Psychotic Hallucinations
Paul
Franceschi
University
of Corsica
http://www.univ-corse.fr/~franceschi
preprint
p.franceschi@univ-corse.fr
Abstract
In
this paper, we describe several factors that can contribute, from the patient's
viewpoint, to the plausibility of psychotic complex hallucinations. We sketch
then a Plausibility of Hallucinations Scale, consisting of a 25-item questionnaire, which aims at evaluating the
degree of plausibility of hallucinations. We also emphasize the utility of
pointing out to the patient the various factors that contribute to the
plausibility of his/her hallucinations, in the context of cognitive therapy for
schizophrenia.
On the Plausibility of Psychotic Hallucinations
We shall focus in
what follows on the plausibility of psychotic hallucinations. My concern will
be with providing an account of complex hallucinations encountered in psychosis
that stresses multiple factors which reinforce, from the patient's viewpoint,
their intrinsic plausibility. The purpose of this paper is then to expose how
hallucinations can seem plausible and credible to the patient. In section 1, we
describe several factors that contribute to the plausibility of hallucinations
occurring in psychosis. We sketch then in section 2 a plausibility scale,
designed to measure accurately the plausibility of hallucinations. In section
3, we point out what could be the impact on cognitive therapy for psychosis of
the present account.
Factors of plausibility of hallucinations
We shall enumerate in what follows several factors that can contribute,
from the patient's viewpoint, to the plausibility of the hallucinations that
he/she experiences. Hallucinations are one major symptom of psychosis. According
to DSM-IV, a hallucination is defined as "A sensory perception that has
the compelling sense of reality of a true perception but that occurs without
external stimulation of the relevant sensory organ". (DSM-IV,
p. 767). By plausibility,
we mean the fact that the patient's abnormal perceptions are seemingly
attributable to an external source (usually, other people). The plausibility
that results from certain phenomenological features of auditory hallucinations
has notably been hinted at by Stephane et al. (2003):
(...)
hearing "multiple voices" is associated with attribution of the
"voices" to others, which is plausible intuitively as well. This
indicates that the patients' experiences of hallucinations could be understood,
intuitively, based on common sense experiences of the world.
In
this paper, we shall expand this idea, by pointing out that multiple factors
are susceptible of congruently strengthening the patient's conviction that
his/her abnormal perceptions come from the external world.
Hallucinations come in a variety of modalities. In order to shed light
on the factors that can lead to the plausibility of hallucinations occurring in
psychosis, it is worth drawing first some useful distinctions.
Unimodal and multimodal hallucinations
Let us begin with the
distinction between unimodal and multimodal hallucinations. Unimodal
hallucinations can be classified into five types, corresponding to our five
sensory pathways: auditory, visual, olfactory, tactile and gustatory.
Multimodal hallucinations are made up of unimodal hallucinations of different
types which occur simultaneously (or quasi-simultaneously). There are
accordingly 26 combinations of multimodal hallucinations (plus 5 unimodal
ones). These latter can be enumerated exhaustively as follows (we also describe
an instance of some common multimodal cases, since it can be useful for
explanatory purposes):
|
n-modal |
case |
instance |
|
|
auditory |
|
|
|
visual |
|
|
1-modal |
olfactory |
|
|
|
tactile |
|
|
|
gustatory |
|
|
|
auditory-visual |
"I saw x sitting on my bed and I heard him saying 'Bastard!'" |
|
|
auditory-olfactory |
"I heard x saying 'I will smoke a cigar!' and at this very moment I smell
a taste of tobacco" |
|
|
auditory-tactile |
"I heard x saying 'You will be stung by a scorpion!' and at this very
moment I felt a sharp sting of pain on my left arm" |
|
|
auditory-gustatory |
|
|
2-modal |
visual-olfactory |
"I saw x on my bed smoking a cigar and I also smell the taste of
tobacco" |
|
|
visual-tactile |
"I saw a scorpion on my left arm and at
this very moment I felt a sharp sting of pain there" |
|
|
visual-gustatory |
"I saw blood dripping from my finger and
it had the taste of blood when I put it on my tongue" |
|
|
olfactory-tactile |
|
|
|
olfactory-gustatory |
|
|
|
tactile-gustatory |
|
|
|
auditory-visual-olfactory |
|
|
|
auditory-visual-tactile |
"I heard x saying 'You will be stung by a scorpion!' and at this very
moment I saw a scorpion on my left arm while feeling a sharp sting of pain
there" |
|
|
auditory-visual-gustatory |
"I heard 'I will harm you' and at this
very moment I saw blood dripping from my finger and it had the taste of blood
when I put it on my tongue" |
|
|
auditory-olfactory-tactile |
|
|
3-modal |
auditory-olfactory-gustatory |
|
|
|
auditory-tactile-gustatory |
|
|
|
visual-olfactory-tactile |
|
|
|
visual-olfactory-gustatory |
|
|
|
visual-tactile-gustatory |
|
|
|
olfactory-tactile-gustatory |
|
|
|
auditory-visual-olfactory-tactile |
|
|
|
auditory-visual-olfactory-gustatory |
|
|
4-modal |
auditory-visual-tactile-gustatory |
"I heard 'I will harm you' and then I
saw blood dripping from my finger, while I felt a sharp pain there. It had
the taste of blood when I put it on my tongue" |
|
|
auditory-olfactory-tactile-gustatory |
|
|
|
visual-olfactory-tactile-gustatory |
|
|
5-modal |
auditory-visual-olfactory-tactile-gustatory |
|
At this step, it should be noted that
multimodal hallucinations retain their force from the plausibility that results
from the simultaneous (or quasi-simultaneous) occurrence of two or more
unimodal hallucinations of different types. For this reason, multimodal
hallucinations retain considerable power with regard to unimodal ones. The
sense of reality that emerges from multimodal hallucinations results from the
fact that several sensory pathways are congruently involved in the
hallucinatory process. Take the example of bimodal hallucinations of the
auditory-visual type: the simultaneous occurrence of an additional visual
hallucination strongly reinforces the sense of reality that emerges from the
auditory hallucination. Consider if, in a single auditory hallucination, a
patient hears the voice of John which insults him/her. Now consider if, instead
of simply hearing the voice, the patient also sees simultaneously John sitting
on his/her bed. This will result in a much greater sense of realism. This shows
how multimodal hallucinations are seemingly highly more plausible and realistic
than unimodal ones. More generally, it illustrates how (n+1)-modal hallucinations appear significantly more real than n-modal ones, a supplementary sensory
pathway being involved in the hallucinatory process.
Factors of plausibility of auditory hallucinations
It is worth
mentioning, to begin with, several factors that can contribute to the intrinsic
plausibility of auditory hallucinations:
(a) structured versus unstructured auditory hallucinations: structured sounds notably
consist of comments on the patient's thoughts or activities, conversations of
several persons, or commands ordering the patient to do things, etc., while on
the other hand, unstructured sounds consist of ringing, buzzing, whistling,
etc.
(b) auditory
hallucinations having an external
versus an internal origin: auditory
hallucinations seemingly coming out from outer space could reinforce the idea
that the voices have an external origin, e.g. are attributable to other people.
(c) the locus (Chadwick et al. 1996, p. 103) --
i.e. the space location -- of auditory hallucinations is also susceptible of
reinforcing their intrinsic plausibility. For consider a patient who hears the
voice of the presenter of the show saying 'Bastard!'. Now this sounds more
realistic if the locus of the voice is the television device rather than the
ashtray. Suppose now that the patient hears a voice saying 'I can read your
thoughts'. Now it sounds more likely to the patient if the voice comes out from
the telephone than from the halogen lamp. The locus of the auditory hallucination
is then another factor which can contribute to the likeliness, from the
patient's viewpoint, of psychotic hallucinations.
(d) bilateral versus unilateral
auditory hallucinations: auditory hallucinations coming indifferenlty from the patient's right or from his/her left are
more plausible than unilateral ones.[1]
(e) time
location related versus unrelated to the patient's thoughts,
emotions or actions (Stephane et al. 2003 make mention of the "relation to
the moment").
(f) phrases versus single words: in this context, phrases, conversations, elaborate
sentences are more plausible than single words.
(g) multiple voices versus single voice (Stephane et al. 2003).
(h) auditory
hallucinations fitting versus not fitting with the patient's desires or
fears: this factor consists of whether the hallucinations experienced by a
patient fit adequately or not with his/her individual fears or desires. For in
the affirmative, it would greatly increase the plausibility of the
corresponding hallucinations. To take an example. The patient is very anxious
about the evolution of his/her illness. He/she hears a voice that says:
"You will relapse next month". Now the content of this auditory
hallucination fits adequately with the patient's own fears. The reason why
auditory hallucinations fitting with desires or fears are more plausible, is
that they are coherent with the
patient's belief system. By contrast, had the content of auditory
hallucinations been unrelated or contradictory with the patient's desires and
fears, the corresponding information would have then resulted in a lack of
coherence with the patient's belief system.
(j) interactive versus noninteractive voices: whether the patient can interact or not with
voices, i.e. discuss or engage in dialog with them.
Factors of plausibility of visual hallucinations
Several factors, on
the other hand, can contribute to the intrinsic plausibility of visual
hallucinations:
(a) formed versus unformed visual hallucinations: formed hallucinations are made up
of figures, faces, morphing objects or scenes. By contrast, unformed
hallucinations consist of dots, lines, geometrical figures, flashes, etc.
(b) ordinary versus bizarre or extraordinary visual hallucinations: for obvious
reasons, objects that look ordinary gain more likeliness than bizarre, unreal
objects.
(c) objects
in color versus in black and white.
(d) visual
hallucinations fitting versus not fitting with surroundings: as noted
by Teunisse et al. (1996), the relationship to surroundings could play an
important role in the plausibility of complex hallucinations. Such or such
unimodal hallucination could fit well (e.g. a person lying on a bed, a scorpion
walking on the ground) or not with surroundings (a figure on the ceiling). Now
it should be apparent that fitting with surroundings visual hallucinations are
consistent with the patient's knowledge of the physical world. This renders,
from the patient's viewpoint, the hallucination very plausible. By analogy with
the locus of auditory hallucinations, fitting with surroundings can be assimilated to the locus -- i.e. space location -- of
visual hallucinations.
(e) bilateral
versus unilateral visual hallucinations.
(f) time
location of visual hallucinations related
versus unrelated to the patient's
thoughts, emotions or actions (e.g. the patient thinks to a scorpion and at
this very moment he/she sees a scorpion on the ground).
(g) animated versus static images.
Plausibility of hallucinations scale
From the above, it
results that it could be useful to measure accurately the plausibility of
hallucinations occurring in psychosis. For this purpose, we shall sketch now a 25-item scale, which is targeted at evaluating the
plausibility of hallucinations experienced by a patient. This scale - which
remains to be tested/validated - consists of a questionnaire which allows for 5
types of ratings: from never (0) to very often (4).
|
item |
questions (0-4) |
|
1 |
does the patient experience auditory hallucinations? |
|
2 |
does
the patient listen hallucinatory structured sounds? |
|
3 |
does the patient experience auditory
hallucinations which come out from outer space? |
|
4 |
does the patient experience auditory
hallucinations whose locus sounds realistic? |
|
5 |
does the patient experience bilateral
auditory hallucinations? |
|
6 |
does the patient experience auditory
hallucinations whose time location is related to the patient's thoughts,
emotions or actions? |
|
7 |
does the patient experience auditory
hallucinations which consist of phrases, conversations? |
|
8 |
does the patient experience auditory
hallucinations with multiple voices? |
|
9 |
does the patient experience auditory
hallucinations whose content fits with his/her fears? |
|
10 |
does the patient experience auditory
hallucinations whose content fits with his/her desires? |
|
11 |
can the patient interact with auditory
hallucinations, i.e. discuss or engage in dialog with them? |
|
12 |
does
the patient experience visual hallucinations? |
|
13 |
does the patient experience formed visual
hallucinations? |
|
14 |
does the patient experience visual
hallucinations with ordinary objects? |
|
15 |
does the patient experience visual
hallucinations in color? |
|
16 |
does the patient experience visual
hallucinations whose locus fits with surroundings? |
|
17 |
does the patient experience bilateral visual
hallucinations? |
|
18 |
does the patient experience visual
hallucinations whose time location is related to his/her thoughts, emotions
or actions? |
|
19 |
does
the patient experience visual hallucinations consisting of scenes or
sequences of animated images? |
|
20 |
does
the patient experience tactile hallucinations? |
|
21 |
does
the patient experience olfactory hallucinations? |
|
22 |
does
the patient experience gustatory hallucinations? |
|
23 |
does
the patient experience bimodal hallucinations (auditory-visual,
auditory-olfactory, etc.)? |
|
24 |
does
the patient experience trimodal hallucinations (auditory-visual-olfactory,
auditory-tactile-gustatory, etc.)? |
|
does
the patient experience quadrimodal hallucinations
(auditory-visual-tactile-gustatory, auditory-olfactory-tactile-gustatory,
etc.)? |
It is worth noting that this 25-item scale can be regarded as non-specific to
psychotic hallucinations. It is also suited to other disorders or illnesses
involving hallucinations. Among these are other mental illnesses, but also
Charles Bonnet syndrome (Teunisse et al. 1996, Menon et al. 2003), epilepsy
(Sachdev 1998; Schwartz & Marsh 2000), etc. In particular, the Charles
Bonnet syndrome occurs in the elderly and is usually associated with ocular
pathology and severe visual impairment. The Charles Bonnet syndrome is
characterized by the presence of complex and persistent visual hallucinations.
The syndrome is usually associated with an absence of hallucinations in other
sensory modalities. It is worth noting that the Charles Bonnet syndrome affects
psychologically normal individuals with full or partial insight and the
patients are accordingly non-delusional. On the other hand, auditory
hallucinations are frequently associated with temporal lobe epilepsy, where
hallucinations in other modalities can also occur.
It is worth
mentioning that the Plausibility of Hallucinations Scale could also be used in
association with other instruments for measuring insight, such as the Beck
Cognitive Insight Scale (Beck et al. 2003) in order to gain more accurate
knowledge of the patient's state. For psychosis is usually associated with lack
of insight into the internal origin of the hallucinations. By contrast, in
other illnesses such as Charles Bonnet syndrome, the patient usually retains
insight into the internal origin of his/her hallucinations (these latter being
often termed pseudo-hallucinations). Perhaps it could be helpful to use in association
an instrument for measuring accurately the insight
into hallucinations, i.e. the belief that the perceptual stimuli have an
internal origin (the patient's 'brain playing tricks': Siddle 2002). The
following scale could notably be used to measure specifically insight into
hallucinations. It consists of a 8-item additional questionnaire, whose structure
parallels that of the Plausibility of Hallucinations Scale:
|
item |
questions (0-100) |
|
1 |
do you believe that the auditory stimuli that
you perceive have an external or an internal (your brain playing tricks)
origin? |
|
2 |
do you believe that the visual stimuli that
you perceive have an external or an internal origin? |
|
3 |
do you believe that the olfactory stimuli
that you perceive have an external or an internal origin? |
|
4 |
do you believe that the tactile stimuli that
you perceive have an external or an internal origin? |
|
5 |
do you believe that the gustatory stimuli
that you perceive have an external or an internal origin? |
|
6 |
do you believe that the bimodal
(auditory-visual, auditory-olfactory, etc.) stimuli that you perceive have an
external or an internal origin? |
|
7 |
do you believe that the trimodal
(auditory-visual-olfactory, auditory-tactile-gustatory, etc.) stimuli that
you perceive have an external or an internal origin? |
|
do you believe that the quadrimodal
(auditory-visual-tactile-gustatory, auditory-olfactory-tactile-gustatory,
etc.) stimuli that you perceive have an external or an internal origin? |
In this context, one
should normally expect that the plausibility of hallucinations rate and the insight into hallucinations be correlated. This should normally be the case for
what concerns psychosis. But it seems also to be the case -- at a lesser degree
-- for other illnesses involving hallucinations, such as Charles Bonnet syndrome.
Along these lines, Teunisse et al. (1996) remarked that among 60 patients,
"11 (18%) had sometimes being deceived for a short period, but this had
happened only when hallucinated objects looked ordinary and fitted
realistically in the surroundings". A similar remark is also made by Menon
et al. (2003).
Impact on Cognitive Therapy
We suggest that the
above emphasis on the plausibility of hallucinations could be usefully
incorporated into the process of cognitive-behavior therapy of schizophrenia (Kingdon
& Turkington 1994, Chadwick et al. 1996, Rector & Beck 2002). The
general idea would be to point out to the patient who experiences highly
plausible hallucinations the different factors that confer to his/her
hallucinations their intrinsic plausibility. Hopefully, this would insert
itself well into the process of cognitive-behavior therapy, whose primary goal
is to help the patient gaining more insight into the nature of his/her
hallucinations and in particular to understand that they do not originate from
an external source. In this context, stressing to the patient the plausibility
of his/her hallucinations, could help him/her understand better how
hallucinations can be self-deceiving.
Let us focus, to
begin with, on multimodal hallucinations. A first step would be to point out
the patient that multimodal hallucinations are capable of seeming very
plausible and realistic. It could then be argued and explained to the patient
that multimodal hallucinations are more plausible than unimodal ones. This could
be illustrated through some examples. This latter strategy could make use of
'what if statements' (Ellis & Dryden 1997). Suppose, could it be said, that
someone experiences, as many people do, hallucinations. To take an example,
suppose that a given person has an auditory hallucination. Now consider if
instead of one single auditory hallucination, he/she experiences simultaneously
one visual hallucination. Wouldn't this multimodal (of the auditory-visual
type) hallucination sound more realistic than a single visual hallucination or
than a single auditory one? Along these lines, it could be pointed out to the
patient that the particular case of multimodal hallucination that he/she
experiences is potentially very realistic and inherently capable of deceiving
him/her.
Once the patient
familiar with the concept of multimodal hallucinations, another goal could be
to learn the patient how to use by herself the preceding taxonomy of multimodal
hallucinations and to apply it when he/she experiences these types of complex
hallucinations. He/she would then be capable of identifying the corresponding
case at hand. Hopefully, this could help the patient rationalize his/her
abnormal perceptions and perhaps accept better the internal origin of his/her
hallucinations as an alternative explanation.
The utility of
classifying multimodal hallucinations would be helpful to the patient, it
seems, to help him/her rationalize and explain the phenomena he/she
experiences. For we should bear in mind that the patient experiences abnormal
phenomena, which are unfamiliar to psychologically normal people. In this
context, helping the patient rationalize, classify and describe accurately the
phenomena of his/her own internal world, appears then as a valuable practical
goal to attain. Accordingly, identifying, recognizing and labeling a given type
of multimodal hallucination could help lessen its associated omnipotence
(Chadwick et al. 1996). This could be helpful to the patient, since it appears
to be a better alternative than simply leave him/her with an unexplained and
upsetting phenomenon. More generally, the fact of identifying the various
factors that render his/her complex hallucinations so plausible could help the
patient gain more insight into the internal origin of his/her hallucinations.
At this step, it should be noted that the present account is notably in line --
for what concerns the delusion that consists in attributing an external origin
to the hallucinations -- with the views emitted by Brendan Maher (1988, 1999),
who sees delusions as a patient's attempt to explain some perplexing and
puzzling phenomena. According to Maher, delusions arise from normal (mainly
rational but occasionally irrational) reasoning applied to abnormal phenomena.
Among these abnormal phenomena which are very perplexing to the patient are the
hallucinations.
Directions for further research
Finally, the above
developments suggest several questions, which could usefully be the subject of
further study. A first question is as follows: (a) Is the plausibility of
hallucinations rate higher in psychosis than in other illnesses involving
hallucinations, e.g. other mental illnesses, Charles Bonnet syndrome, temporal
lobe epilepsy, etc.? A comparison of the plausibility of hallucinations rate
occurring in schizophrenia and other illnesses involving hallucinations could
be made accordingly. We suggest that such comparison could provide some useful
information about the relationships of these illnesses (Sachdev 1998). Although
schizophrenia (paranoid subtype) should prima facie involve a higher rating, it
seems that an accurate measure of the degree of plausibility of hallucinations
could result in some interesting information. Along these lines, a comparison
of the plausibility of hallucinations ratings occurring in different subtypes
of schizophrenia could also be made.
The above
Plausibility of Hallucinations Scale is also designed to allow for comparisons
between different chronological states in the same patient. This suggests a
second type of question: (b) Does the plausibility of hallucinations rating
evolve during the course of schizophrenia? Along these lines, Nayani &
David (1996) observed an increase in the complexity of auditory hallucinations
over time, seemingly related to lesser distress and better coping. An
additional question would also be: does the plausibility of hallucinations
rating increase during the period that precedes a relapse? A similar question
could be raised for other illnesses involving hallucinations. In this context,
Menon et al. (2003) reported accordingly that "Elementary hallucinations
may progressively evolve into complex visual hallucinations" in the
Charles Bonnet syndrome.
The following types
of question extend the two preceding questions to the correlation between the
ratings of the plausibility of hallucinations and of the insight into
hallucinations. It follows: (c) Is there a significant difference in the
correlation of the plausibility of hallucinations rating and of the insight
into hallucinations rating, in different illnesses involving hallucinations,
and also in different subtypes of schizophrenia? And also: (d) Does this latter
correlation evolve during the course of the illness in the same patient?
Lastly, a fifth
interesting question goes as follows: (e) Is the plausibility rate of
hallucinations occurring in schizophrenia correlated with the I.Q. of the
patient, i.e. do patients with a high I.Q. more frequently experience complex
hallucinations with a high level of plausibility? In other words, is the
following hypothesis confirmed: The higher the I.Q., the higher the
plausibility of hallucinations rating? Hopefully, the answer to these questions
will provide some information that might well be useful to the understanding of
the illness and to cognitive-behavior therapy of schizophrenia.
I thank Peter Brugger
and Hélène Verdoux for very useful comments on an earlier version of this
paper.
|
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[1] I owe the suggestion to include the bilateral/unilateral distinction related to hallucinations in all modalities to Peter Brugger.