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Symptomatology and social inference: Atheory of mind study of schizophrenia andpsychotic affective disorderDominic Marjoram a , Clare Gardner b , Jonathan Burns c , Patrick Miller a ,Stephen Lawrie a & Eve Johnstone aa Royal Edinburgh Hospital, Edinburgh, UKb Nottingham City Hospital, Nottingham, UKc University of KwaZulu-Natal, Durban, South AfricaPublished online: 10 Sep 2010.

To cite this article: Dominic Marjoram , Clare Gardner , Jonathan Burns , Patrick Miller , Stephen Lawrie &Eve Johnstone (2005): Symptomatology and social inference: A theory of mind study of schizophrenia andpsychotic affective disorder, Cognitive Neuropsychiatry, 10:5, 347-359

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Symptomatology and social inference: A theory of

mind study of schizophrenia and psychotic affective

disorder

Dominic Marjoram

Royal Edinburgh Hospital, Edinburgh, UK

Clare Gardner

Nottingham City Hospital, Nottingham, UK

Jonathan Burns

University of KwaZulu-Natal, Durban, South Africa

Patrick Miller, Stephen M. Lawrie, and Eve C. Johnstone

Royal Edinburgh Hospital, Edinburgh, UK

Introduction. There is evidence that certain patients with schizophrenia havedeficits in theory of mind (ToM) capabilities. It is, however, unclear whether theseare symptom or diagnosis-specific.Methods. A ToM hinting task was given to 15 patients with a DSM-IV diagnosis ofschizophrenia, 15 patients with affective disorder and 15 healthy controls. Severityof the current psychopathology was measured using the Krawiecka standardisedscale of psychotic symptoms (Krawiecka, Goldberg, & Vaughan, 1977); IQ wasestimated via the Ammons and Ammons Quick Test (Ammons & Ammons, 1962).Results. The group with schizophrenia performed significantly worse than theaffective and control groups. Poor performance on the hinting task was found to besignificantly related to the presence of positive symptoms (instead of negativeones) and specifically related to delusions and hallucinations. These findingsremained when covariance for potentially confounding variables was applied.Conclusions. Individuals with high levels of delusions and hallucinationsperformed significantly worse on this ToM task, regardless of diagnosis, implyingToM impairment is not exclusive to schizophrenia but is evident in other forms ofpsychosis. Between-group analyses showed the schizophrenia group had asignificicantly poorer performance on this task than the others.

Correspondence should be addressed to Dominic Marjoram, University Department of Psy-

chiatry, Kennedy Tower, Royal Edinburgh Hospital, Morningside Park, Edinburgh EH10 5HF, UK;

e-mail: D.K.S. Marjoram@sms.ed.ac.uk

# 2005 Psychology Press Ltd

http://www.tandf.co.uk/journals/pp/13546805.html DOI:10.1080/13546800444000092

COGNITIVE NEUROPSYCHIATRY

2005, 10 (5), 347±359

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Theory of mind

The term theory of mind (ToM), sometimes referred to as mind-reading (Baron-

Cohen, 1995) and mentalising (Corcoran, Cahill, & Frith, 1997), was first coined

by Premack and Woodruff (1978) and refers to the ability of individuals to

correctly determine the intentions and behaviour of others. This is a necessary

skill for successful complex social interactions and it is known to be compro-

mised in autism and schizophrenia (Abu-Akel, 2003). In schizophrenia, the

degree of impairment of ToM fluctuates in relation to psychotic episodes and

severity of particular symptoms. Individuals with formal thought disorder,

paranoid delusions, and chronic negative symptoms perform the worst on ToM

tasks. Frith (Frith 1992) hypothesised that positive symptomatology could result

in an impairment in ``metarepresentation'', this being the ability to represent

abstract cognitive processes about oneself and others.

Using the Hinting Task, Corcoran, Mercer, and Frith (1995), found symptom-

specific findings consistent with Frith's (1992) model. In Corcoran's original

study, patients with schizophrenia and paranoid delusions and related positive

features, and also those with negative features had the greatest difficulty with the

hinting task. The present study aims to develop the hinting task. The major

difference between the present study and that of Corcoran et al. (1995) is that in

Corcoran's original study the psychiatric controls did not have psychotic illness.

The study of ToM deficits in psychiatric disorders other than schizophrenia is

currently a sparsely investigated area. Doody, Gotz, Johnstone, Frith, and Owens

(1998) had 12 patients with nonpsychotic affective disorder as one of their

experimental groups and found no observed ToM deficits among them. Kerr,

Dunbar, and Bentall (2003) exclusively studied nonpsychotic bipolar groups

against healthy controls and found impaired ToM performance in symptomatic

(both manic and depressed) bipolars. Drury, Robinson, and Birchwood (1998)

had a group of 10 deluded psychotic individuals (the majority of who were

schizoaffective) and 12 nonpsychotic depressed patients and both groups sig-

nificantly outperformed a schizophrenia group on ToM tasks.

The aims of this study were to compare performance on a ToM task in

patients with affective psychoses and healthy controls, with that of patients with

schizophrenia, to test the hypothesis that a deficit in ToM skills is associated

with particular psychotic symptoms (specifically delusions and hallucinations),

regardless of diagnosis.

METHODS

Participants

Fifteen people with a DSM-IV diagnosis of schizophrenia and 15 with DSM-IV

bipolar disorder or major depressive illness (seven of which were bipolar and the

remaining eight were classified as severe depressive illness) were recruited. All

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were aged 18±60 years. These patients were drawn from inpatients of an acute

psychiatric ward, outpatients, and attendees of the day hospital at the Royal

Edinburgh Hospital. All participants gave written informed consent to partici-

pate in the study, which was approved by the local hospital ethical committee.

The current level of overall intellectual functioning was estimated using the

Quick Test (Ammons & Ammons 1962). In addition, a control group of 15

healthy volunteers were studied, derived from staff of the Department of Psy-

chiatry. Individuals with any form of autistic spectrum disorder or head injury

were excluded.

Demographic characteristics of both subjects and controls are shown in Table

1 and the patient medications are detailed in Table 2.

To take account of current symptomatology, patients were also assessed using

a standardized scale for rating chronic psychotic patients (Krawiecka et al., 1977).

Scores on a 5-point scale are assigned to symptoms experienced over the previous

week. Ratings were given on a 5-point scale (where 0 = absent, 1 = mild, 2 =

moderate, 3 = Marked, 4 = severe) for coherently expressed delusions, hallu-

cinations, incoherence/irrelevance of speech, and incongruity giving a maximal

possible score of 16 for positive symptoms. Likewise, negative symptoms were

rated for poverty of speech and flattened affect giving a maximal possible score of

8 and the nonspecific symptoms of depression, anxiety, and psychomotor

retardation were assessed giving a possible maximal score of 12.

In order to look closely at the positive symptomatology of delusions and

hallucinations and to see what effect these had on ToM capabilities, the Kra-

wiecka scores for these were used in the following ways: (1) Presence of

delusions against performance: patients were divided into those scoring 0 and 1

(none to low) and those scoring 2±4 (moderate to severe). (2) Presence of

hallucinations against performance: likewise, those scoring 0±1 and those

scoring 2±4.

The Hinting Task. The task comprises 10 short passages involving two

characters, and each scenario ended with one of the characters dropping a very

obvious hint. The subject is then asked what the character really meant when he/

she said this. An appropriate response is given a score of 2 and the interviewer

TABLE 1Demographic details of the subject groups: Means and (standard deviations)

Group n (m:f) Age IQ

Duration of

illness (yrs)

Schizophrenic 15 (13:2) 28.3 (8.2) 96.5 (10.0) 11.3 (5.1)

Affective 15 (6:9) 41.7 (9.7) 101.8 (10.8) 17.3 (7.4)

Healthy controls 15 (10:5) 34.3 (12.7) 106.0 (9.7)

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proceeds on to the next story. However, if the subject fails to give an appropriate

response (e.g., by simply paraphrasing what was said and thus using no infer-

ential skills), a further sentence is added to the story containing an even more

obvious hint. Then the subject is asked what the character wants the other one to

do. A successful response is given a score of 1 whilst a score of 0 is given for an

inappropriate one. Some of the patients (7 schizophrenic and 8 affective) and

controls (9) had the Corcoran 10 hinting tasks and the remainder did the task of

new hinting sentences devised for this study (the Gardner tasks). All hinting

items were read aloud to the subjects, and were repeated as required, to ensure

adequate encoding of the information presented and overcome the poor prose

recall associated with schizophrenia (Shallice et al., 1994). Furthermore, in order

to reduce the potential memory load of the task, a sheet containing all the tasks

was placed in front of the subjects for them to read if they so desired. The 10

new hinting task items are in the Appendix. These were selected, in consultation

with Professor Chris Frith, from a pool of 20 devised for consideration.

Statistical analysis. Data analysis was carried out using SPSS for Windows

Version 11.0. Mean Hinting Task scores were compared between groups with an

ANOVA and post hoc Tukey HSD. Relations of delusions and hallucinations

and the Krawiecka totals for positive and negative symptoms were then

examined with multiple regression with current IQ, age, sex, type of task

(Corcoran or present), and medication dose as covariates.

RESULTS

Diagnosis

There was a significant effect of diagnosis in terms of performance on the

hinting task (F = 3.27, p < .05). Using Tukey's HSD test, the schizophrenia

group performed less well than either the controls or patients with affective

TABLE 2Medication details of the patient groups

Medication

Schizophrenics

(n = 15)

Affectives

(n = 15)

Typical antipsychotic only 4

Typical antipsychotic + Anticholinergic 5

Atypical antipsychotic only 5

Atypical antipsychotic + Anticholinergic 1

Antidepressant only/antidepressant + other

nonantipsychotic medicine

9

Antidepressant + Typical antipsychotic 5

Antidepressant + atypical antipsychotic 1

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disorder (p < .0001). There was no significant difference in performance

between these latter two groups (Table 3).

It is, however, clear that the groups differ in terms of IQ, though both are well

within the normal range. There is also a marked difference with respect to age

and sex distributions. Given these variables, multiple regression was performed,

with allowances made for variations in type of test given, age, sex, and IQ. The

difference in performance between schizophrenics and controls was still highly

significant (p < .001). The variables of age, sex and IQ were then analysed

against ToM performance and it was found that none of these had a significant

affect.

However, when data were analysed in terms of whether subjects received the

original (Corcoran-devised) or the newly developed hinting task (Gardner-

devised), via an independent samples t-test, it appeared that the latter was more

difficult; giving a mean of 16.8 (SD = 2.8, n = 21) in comparison to a mean of

18.3 (SD = 1.6, n = 24) for the original test (p < .005). There was, however, no

significant task type by group interaction.

Symptoms

When data were analysed using scores from the Krawiecka 5-point scale for

both the schizophrenia and affective disorder patients it was found, as shown in

Table 4, that poor performance by patients was significantly associated with the

presence of both moderate to severe delusions and hallucinations, regardless of

diagnostic group. No significant group effect over and above symptom effect

was found.

Further investigation via multiple regression analysis, allowing for age, sex,

type of hinting test, and IQ, showed a significant relationship between positive

symptoms and performance on the hinting tasks (p = .01, beta-value of 7.558)

as shown in Table 5.

CONCLUSIONS

The major finding of this study is that there was an observed deficit in ToM

skills on this task of simple social inference that was associated with particular

psychotic symptoms. This was not specific to patients with schizophrenia, but

TABLE 3Performance on the hinting task between the groups: Means (and standard deviations)

Schizophrenics

(n = 15)

Affectives

(n = 15)

Controls

(n = 15)

Hinting score 15.5 (2.2) 18.2 (1.7) 19.2 (1.1)

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included those with psychotic symptoms in the context of affective disorder. In

this respect, this study differs to the original hinting task study of Corcoran et al.

(1995) where psychiatric controls did not have psychotic illness.

The performance of the group with schizophrenia was significantly poorer

than that of both the affective and control groups. This finding persists even

when current level of intellectual functioning is taken into account. This was

expected and in agreement with all previous ToM and schizophrenia literature

and lends further support to the idea for a specific cognitive deficit in these

patients. However, given the findings of this study, this deficit may not be

specific for schizophrenia but occurs in psychoses in general and may involve

other areas of cognition as well as ToM.

Symptom-specific findings

Significant problems performing the hinting task were encountered in patients

with high levels of delusions and hallucinations (positive correlation). It was

found that individuals with moderate/high (2±4) scores for delusions and hal-

lucinations had significantly lower hinting task scores than those patients with

mild/no delusions or hallucinations.

TABLE 4Performance on the hinting task according to presence or absence of delusions and

hallucinations: Means (and standard deviations)

Mean

hinting score

N SD Sig.

(ANOVA)

Delusions

Score 0±1 (None/Low) 17.7 6 (1.8) ±

Score 2±4 (Mod/High) 16.5 24 (2.4) p = .016

Hallucinations

Score 0±1 (None/Low) 17.8 18 (1.7) ±

Score 2±4 (Mod/High) 15.5 12 (2.5) p = .013

TABLE 5Krawiecka positive, negative, and nonspecific symptom score averages and

performance on hinting task: Means (and standard deviations)

Krawiecka

symptoms

Mean

Krawiecka score

Patients

(N)

Sig. for poorer

task performance

Negative symptoms 2.2 (1.9) 23 p = .076

Nonspecific symptoms 4.5 (2.4) 29 p = .342

Positive symptoms 4.4 (2.9) 27 p = .01

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When the Krawiecka et al. (1977) scores for positive and negative symptoms

were compared through regression analysis, positive symptoms were found to be

highly significantly associated with lower scoring on the hinting task. As far as

negative symptoms were concerned, there was no significant association but

there was a trend (p = .076) for higher symptom scores to be associated with

lower hinting task scores as was found in the original Corcoran study.

Antipsychotic medication dose at time of testing was recorded for each

patient and using standard published tables (Atkins, Burgess, Bottomly, &

Riccio, 1997; Woods, 2002) was converted into daily chlorpromazine equivalent

dosage. No significant correlation was found between this measure and the

hinting task. Antidepressant dosage was also recorded and was graded as either a

low dose [if the daily dose was less than or equal to half the British National

Formulary (BNF) (2002) recommended daily dosage] or a high dose (if the daily

dose was greater than half the BNF recommended daily dosage). The biserial

correlation with the hinting task performance was also found to be non-

significant although there was a slight trend (p = .063) implying the greater the

dose the better the performance on the task.

It may be argued that since the development of schizophrenia occurs during

adolescence or early adulthood, and that ToM skills are acquired in childhoodÐ

generally by the age of four years (Leslie, 1987), it is likely that such patients

developed mentalising skills to a normal level before becoming compromised by

the subsequent onset of the illness. If this were so, these patients would be

accustomed to making social inferences, and would continue to do so, appar-

ently unaware that their judgements are incorrect. This may also apply to those

individuals with affective disorder who had significantly impaired ToM

performance.

Metarepresentation

The finding for positive symptomatology in general and specifically delusions

and hallucinations being significant for poor performance on the hinting task

supports Frith's (1992) metarepresentation theory. Metarepresentation is the

ability to represent both one's own mental state and those of others, in this way,

Frith's theory views schizophrenia as a disorder of the representation of mental

states.

Individuals with schizophrenia who have predominately negative symptoms

can be thought as having a ToM deficit in that they lack representational

understanding of mental states. However, in individuals with positive symptom

schizophrenia there is a theory of mind impairment where over attribution

of mental states occurs: This has been labelled as a ``hyper-theory of mind''

(Abu-Akel, 1999, 2003; Abu-Akel & Bailey, 2000).

Using this hyper ToM concept, a mental state impairment continuum can be

envisaged, as described by Abu-Akel and Bailey (2000): The first variety of

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ToM impairment involves having no representational understanding of mental

states; the second involves having representational understanding of mental

states, but (due to a reality bias), a deficit in application of this understanding;

the third variety involves representational understanding of mind but over

attribution of mental states or over generation of hypotheses about mental life

(such as paranoid delusions).

How positive symptoms, particularly those of delusions and hallucinations,

actually interfere with ToM capabilities is not known and it remains to be

elucidated whether there is a special relationship between mentalising cap-

abilities and symptoms (Frith, 2004).

State vs. trait

Whether compromised ToM function in individuals is a state effect that fluc-

tuates with symptom severity has been studied by incorporating a remission

group into the experimental design of several studies, allowing psychotic and

nonpsychotic individuals with the same disorder to be compared. Corcoran et al.

(1995, 1997) and Frith and Corcoran (1996) found that there was no sig-

nificantly impaired ToM performance in the remission groups compared with

the control groups. Drury et al. (1998) used a novel approach of testing a

schizophrenia group in an acute phase and in remission, against a nonschizo-

phrenia psychosis group and a depressed group. There were significant differ-

ences between the schizophrenia group in the acute phase and the other groups

on a second order ToM task; however these differences disappeared in remis-

sion. However, Herold, Tenyi, Lenard, and Trixler (2002) found contrary results,

in that their schizophrenia group in remission did perform significantly worse

than the control group. These studies used different ToM tasks, and had dif-

ferences in group sizes, as well as varying average lengths of patient illness and

medication duration.

The potential alternative to a transient state effect which fluctuates with

symptom severity is the possibility that the observed ToM deficits are a trait

effect, underpinned by a genetic predisposition to schizophrenia. This theory has

been investigated by testing relatives of individuals with schizophrenia on ToM

tasks: Wykes, Hamid, and Wagstaf (2001) found siblings of people with schi-

zophrenia to perform significantly worse than control participants on ToM tasks.

Janssen, Krabbendam, Jolles, and Van Os (2003) found first degree relatives to

perform better than the schizophrenia group but worse than the control group on

the hinting task.

These findings suggest the possibility that in some forms of schizophrenia

there is a failure of ToM capacities to fully develop and this could be a precursor

to the disorder, and could at least potentially be a diagnostic marker for those at

enhanced risk.

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Type of Hinting Task administered

As mentioned previously, there were two sources of the 10 hinting tasks given to

subjects. The original 10 tasks used by Corcoran et al. (1995) and a new set of

10 (see Appendix) written specifically for this project. It was decided to give

subjects all of one set as opposed to a mixed set to allow for statistical analysis

in order to see whether the two tasks could be used interchangeably in future

studies or needed to be kept separate due to different degrees of difficulty. It was

found that the Gardner tasks were in fact significantly harder than the original

Corcoran ones (means of 18.3 vs. 16.8, respectively). This particular study is a

pilot study for a larger planned study that will be looking at a selection of

clinical subgroups. These will include individuals at high risk of schizophrenia

for genetic reasons (Edinburgh High Risk Cohort) and schizotypal individuals

with mild learning disability (comorbids cohort). The mild LD group may be

able to perform the easier sentence test. Likewise, a harder set of hinting sen-

tences will be able to help limit the ceiling effect in adult controls and could

perhaps be used in conjunction with easier sentences to produce a graded dif-

ficulty hinting task.

Role of IQ

The extent to which IQ plays a role in the understanding of ToM remains to be

fully elucidated. An earlier study found that out of several schizophrenic sub-

groups, only in paranoid patients were there difficulties in understanding the

ToM tasks associated with lower IQ. The authors took this as an implication that

those paranoid patients with higher IQs could possibly compensate ToM deficits

by solving the tasks using general capacities (Pickup & Frith, 2001). Doody et

al. (1998) found that schizophrenic patients with comorbid learning disability

performed worst on ToM tasks and interpreted this as a possible cumulative

effect of lowered IQ and psychopathology.

In this particular study, the findings were found to still be significant after the

IQ differences were covaried out, hence implying that IQ was not entirely

responsible for the between-group differences in performances on the hinting

task. There is, however, a need to reliably distinguish between a compromised

information-processing capacity, IQ and a general ToM impairment (As sug-

gested by BruÈne, 2003).

Limitations

With this being a pilot study testing new hinting sentences, the size of the groups

was relatively small (n = 15). This size constraint meant that the schizophrenia

group was heterogeneous, unlike the original hinting study (Corcoran et al.,

1995), in which the schizophrenia group was symptom-orientated and divided

into particular subgroups (e.g., passivity and paranoid for the different delusion

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types). The use of the Krawiecka standardised scale of psychotic symptoms, did

however, allow the groups to be subdivided into subgroups for symptom severity

(none/low and moderate/severe for delusions and hallucinations). Cumulative

scores for positive symptoms (coherently expressed delusions, hallucinations,

incoherence/irrelevance of speech and incongruity), negative symptoms (pov-

erty of speech, flattened behaviour), and nonspecific symptoms (depression,

anxiety, and psychomotor retardation) were then used in further analysis. In

terms of negative symptoms our findings are not significant (see above) and this

is in contrast with the finding of Corcoran et al. (1995) in which this group of

patients produced the worst scores on the task. It may well be that this difference

is due to the fact that this study did not have a particular subgroup of schizo-

phrenia patients with the particular diagnosis of negative features.

It is apparent from Table 1 that the age, sex ratios, and IQs were not matched

across the groups. However, as mentioned previously, regression analysis was

performed to covary for these possible limitations. Medication dose was also

covaried for as it is widely believed that long-term use of medication, particu-

larly antipsychotics, may have a significant impact on cognitive functioning.

This study has confirmed, as hypothesised, that the schizophrenia group

performed less well as either the affective and control groups on this ToM task.

As regards the symptomatology of psychosis, the study found that poor per-

formance could be linked to positive symptoms, independent of diagnosis. The

presence of hallucinations and delusions was also found to be significant. These

findings add validation to the earlier mentioned Frith (1992) model linking

positive symptomatology of schizophrenia to mental state impairments. With

regard to the major finding of this study, this model could be enlarged to

encompass all psychoses.

We think that the hinting task is an adequate tool for testing ToM abilities in

adults, and that this study lends further support to the argument that there are

symptom-specific difficulties in the ability to infer mental states of others.

Manuscript received 2 April 2004

Revised manuscript received 21 May 2004

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APPENDIX

The 10 new hinting tasks used in conjunction with the 10 Corcoran tasks

Lisa is about to leave the house when her father's car pulls up in the driveway. When he enters she

says to him: ``I really need to go shopping, but it's so far away and the rain is terrible''.

Question: What does Lisa really mean when she says this?

Hint: Lisa goes on to say: ``It's only five minutes in the car''.

Question: What does Lisa want her father to do?

Alan is watching television, and his wife Jill sits down to join him. She says: ``I see you're watching

the football. Isn't there anything else on at the moment?''

Question: What does Jill really mean when she says this?

Hint: Jill then says to Alan: ``I thought there was a good play on the other channel''.

Question: What does Jill want Alan to do?

Sarah is spending the morning with her next-door neighbour Caroline, having coffee. They are

talking about Sarah's forthcoming holiday abroad, when Sarah says to Caroline: ``I'm worried that

all my plants will be dead by the time I get back''.

Question: What does Caroline really mean when she says this?

Hint: Caroline then says to Sarah: ``I have a spare key for the front door''.

Question: What does Caroline want Sarah to do?

Jack and his father are talking about the recent form of the local football team, which they both

support. Jack says: ``You know United are playing at home to their big rivals this weekend. I'm sure

it will be very exciting.''

Question: What does Jack really mean when he says this to his father?

Hint: Jack goes on to say: ``I have never been to watch a football match''.

Question: What does Jack want his father to do?

Jim and his brother Richard are getting ready for work in the morning. Jim goes to the bathroom and

finds that Richard is about to use the shower, and says to him: ``I've got an early start today and I'm

running late''.

Question: What does Jim really mean when he says this to Richard?

Hint: Jim goes on to say to Richard: ``It won't take me long to get ready''.

Question: What does Jim want Richard to do?

Harry and Chris work together in the same office. One day Harry says to Chris: ``I would really like

an extra long lunch break today, as I have to go to the bank. Will you be going out for lunch today?''

Question: What does Harry really mean when he says this?

Hint: Harry then says to Chris: ``Do you think our boss would mind if only one of us were here?''

Question: What does Harry want Chris to do?

On a weekday evening, Martin goes to see his friend Lucy at home. He is trying to persuade her to go

out for a meal, but she says: ``I'm really busy writing a report tonight. I don't even have time to

chat''.

Question: What does Lucy really mean when she says this?

Hint: Lucy then says: ``I really have to be getting on with my work, is there someone else you could

ask''.

Question: What does Lucy want Martin to do?

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Two children, Emma and Katie are playing, when Emily breaks an old statue belonging to Katie's

mother. Emma says to Katie: ``If your Mum finds out it was me that broke it, I won't be allowed to

come here anymore''.

Question: What does Emma really mean when she says this?

Hint: Emma then says to Katie: ``She wouldn't punish you though''.

Question: What does Emma want Katie to do?

Tony and his girlfriend Alison are giving a dinner party at their new flat. They are going through the

list of guests when Alison exclaims: ``Oh! It says here you've invited your ex-girlfriend. Is that

right?''

Question: What does Alison really mean when she says this?

Hint: Alison goes on to say to Tony: ``I don't get on with her very well''.

Question: What does Alison want Tony to do?

Simon is enjoying an evening out at the pub with his friend Gareth. Gareth is about to buy some more

drinks when Simon says: ``I have a very busy day tomorrow, and I need to be at my best''.

Question: What does Simon really mean when he says this?

Hint: Simon then says to Gareth: ``We have already had quite a lot to drink''.

Question: What does Simon want do?

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