Cognición Esquizotipia y Esquizofrenia

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Aspects of cognitive functioning in schizotypy and schizophrenia: Evidence for a

continuum model

Mary Cochrane a,, Ian Petch b, Alan D. Pickering c,1

a Division of Psychological Medicine and Psychiatry, Institute of Psychiatry, 4 Windsor Walk, London SE5 8BB, United Kingdomb Early Intervention Team, Springeld University Hospital, 61 Glenburnie Road, London SW17 7DJ, United Kingdomc Department of Psychology, Goldsmiths College, University of London, SE14 6NW, United Kingdom

a b s t r a c ta r t i c l e i n f o

Article history:Received 27 August 2011

Received in revised form 7 February 2012

Accepted 8 February 2012

Keywords:

Schizotypy

Schizophrenia

Cognitive functioning

Continuum approach

This research consisted of two studies, the fundamental aim of which was to delineate the pattern of relationshipsbetween measures of cognitive task performance and both symptom subtypes in schizophrenia and their

corresponding schizotypal personality traits in healthy individuals. Study 1 compared these relationships in healthy

individuals using the Schizotypal Personality Questionnaire (SPQ) and Study 2 assessed the relationships between

symptomatology assessedusing the Scale for the Assessment of Positive Symptoms and Scale for the Assessment of

Negative Symptoms (SAPS/SANS) and cognitive task performance in a group of patients with schizophrenia. The

contribution ofuid intelligence to task performance was also examined. In Study 1 high levels of negative schizo-

typy were associated with reduced verbaluency, and high levels of disorganised schizotypy were associated with

reduced negative priming in the healthy participants. In Study 2, closely corresponding relationships between

symptom measures and these tasks were found in the patients with schizophrenia. The associations between

the symptom and cognitive measures were independent of the effects ofuid IQ on performance.

2012 Elsevier Ireland Ltd. All rights reserved.

1. Introduction

A growing body of research suggests that symptoms of schizo-

phrenia and corresponding elevated schizotypal personality scores

in non-clinical samples are associated with similar disruptions in cog-

nitive functioning. This accords with the fully dimensional approach

to schizophrenia, which proposes that the dimension of schizotypy

lies on a continuum that begins with normality and proceeds towards

the schizophrenia spectrum disorders, with schizophrenia at the

upper end (Claridge and Beech, 1995).

Verbal uency (VF)and negative priming (NP) are two cognitive phe-

notypes which are consistently found to be impaired in patients with

schizophrenia and in healthy individuals scoring high on measures of

schizotypal personality.However, relationshipsbetween aspectsof symp-

tomatology and cognitive performance are not always consistent and, in

the case of negative priming, there is limited research assessing the way

in which differential aspects of symptomatology relate to performance.

Verbal uency is a commontest of response generation, in which par-

ticipants are asked to generate, in a one-minute interval, as many words

as possiblethat begin witheach of three letters.Patients withschizophre-

niatypically generatefewer words thancontrols on VF tasks andnegative

symptoms are associated with these decits (Liddle and Morris, 1991;

Frith, 1992). Negative symptomratings are also correlated withimpairedVF in patients with schizotypal personality disorder (Diforio et al., 2000),

and negative schizotypy is positively associated with VF decits in the

healthy siblings of schizophrenic patients (Franke et al., 1993).

Reported relationships between schizotypal personality traits and VF

in healthy participants are somewhat inconsistent. Tsakanikos and

Claridge (2005) found that reduced VF was associated with increased

O-LIFE(Oxford-Liverpool Inventory of Feelings and Experiences) negative

schizotypy, but also found thatgreaterVF was associated with high levels

of O-LIFE positive schizotypy. Relationships have been found between

reduced VF and high scores on both negative and positive schizotypy

(Barrantes-Vidal et al., 2003) and between reduced VF and high scores

on both negative and disorganized schizotypy, or positive schizotypy

(Ruiz et al., 2008). These latter studies employed a cluster-analytic rather

than a dimensional approach to schizotypal personality, which may (at

least partially) explain the differential ndings.

The NP paradigm is believed to assess selective attention and cog-

nitive inhibition (Tipper, 1985). Reduced negative priming has been

found in patients with schizophrenia (Beech et al., 1989; Park et al.,

1996; Williams, 1996; Peters et al., 2000), although some authors

have not observed NP decits in patients (Laplante et al., 1992;

Baving et al., 2001). A possible explanation for this discrepancy is pro-

vided byMoritz et al. (2001).There is a striking paucity of research

assessing relationships between aspects of symptomatology and neg-

ative priming.Williams (1996)reported an association between both

positive and disorganised symptomatology and reduced NP in schizo-

phrenia, although this nding is yet to be replicated. Impaired NP in

Psychiatry Research 196 (2012) 230234

Corresponding author. Tel.: +44 207 848 0656.

E-mail addresses:[email protected](M. Cochrane),

[email protected](I. Petch),[email protected](A.D. Pickering).1 Tel.: +20 7919 7334.

0165-1781/$ see front matter 2012 Elsevier Ireland Ltd. All rights reserved.

doi:10.1016/j.psychres.2012.02.010

Contents lists available at SciVerse ScienceDirect

Psychiatry Research

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healthy participants appears to be primarily associated with positive

schizotypy (Peters et al., 1994; Park et al., 1996).

The current research consisted of two studies, which attempted to

ascertain whether relationships between aspects of symptomatology/

schizotypal personality and performance on two popular cognitive

tasks would be consistent across a group of healthy participants and

a group of patients with schizophrenia. A consistent patternof relation-

ships would provide convincing evidence for the continuum approach

to schizophrenia and uniquely demonstrate that both clinical symp-toms and non-clinical characteristics impact in a similar way on cogni-

tive functioning. A measure of uid IQ was included to investigate

whether any relationships between symptomatology and cognition

were maintained despite differences in a general cognitive ability.

In the healthy participants in Study 1, it was expected that higher

levels of SPQ (Schizotypal Personality Questionnaire) negative schizo-

typy would be associated with reduced verbaluency,and that higher

levels of SPQ positive or disorganised schizotypy would be associated

with reduced negative priming. In the patient group we expected the

same pattern of relationships between symptomatology and cognitive

task performance, using the Scale for the Assessment of Positive

Symptoms/Scale for the Assessment of Negative Symptoms (SAPS/

SANS) inventory (Andreasen, 1983, 1984). Finally, it was assumed

that these effects would be independent of the expected positive rela-

tionships between uid IQ and the cognitive measures.

2. Method

2.1. Ethical approval

Ethical approval for Studies 1 and 2 was obtained from the Psychology Department

Ethics Committee at Goldsmiths College. For Study 2, ethical approval was also

obtained from the South West London NHS Local Research Ethics Committee.

2.2. Participants

Study 1 consisted of a convenience sample of 100 participants (50 females and 50

males), recruited from the student population at Goldsmiths College, University of

London. Participants were recruited by means of advertisements posted around the

college and received either course credits (psychology students) or a small remunera-

tion for their participation. Age range was between 18 and 45 years (M=25.00,

S.D.=6.09). Seventy one percent of 99 participants were native English speakers (lan-

guage information was not available for one participant), although all participants

were uent in English. The mean number of years spent in education was

16.17 years (S.D.= 2.85). Exclusion criteria, determined through self-report, were pre-

vious or current psychological or neurological disturbance, a serious physical medical

condition, or currently taking psychoactive medication.

Twenty patients with schizophrenia took part in Study 2: 10 were inpatients and 10

were living in the community. There were 18 males and 2 females. All patients had an

ICD-10 diagnosis of schizophrenia, were taking atypical neuroleptic medication, and

were uent in English. Age range was between 18 and 50 years (M=34.24,

S.D.=8.42). Patients with a diagnosed substance abuse disorder, concomitant neurolog-

ical disorder or serious physical medical condition were excluded from the study. The in-

patients were recruited from three wards at Springeld University Hospital, South West

London, and were tested in a quiet consulting room on the ward. The community pa-

tients were recruited from three Community Mental Health Teams in the South West

London area and were tested at an outpatient clinic that they regularly attended.

2.3. Schizotypal Personality Questionnaire (SPQ, Raine, 1991)

Study 1

The SPQ is a forced choice (Yes/No) self-report inventory which contains 74 items

and divides into nine subscales based on the nine criteria for DSM-III-R schizotypal per-

sonality disorder (American Psychiatric Association, 1987). These subscales are Ideas of

Reference (IoR), Unusual Perceptual Experiences (UPE), Odd Beliefs or Magical Thinking

(OBMT), Paranoid Ideation (PI), Excessive Social Anxiety (ESA), No Close Friends (NCF),

Constricted Affect (CA), Odd or Eccentric Behaviour (OEB), and Odd Speech (OS). The

SPQ also sub-divides into three factors: CognitivePerceptual, Interpersonal and Disorga-

nised;whichare regarded as non-clinical analoguesof thepositive, negative anddisorga-

nised symptoms of schizophrenia respectively (Raine et al., 1991).

2.4. Clinical Interview Schedule (SAPS/SANS)Study 2

The SAPS/SANS consist of a total of 51 items, with each item scored between 0 (ab-

sence of a symptom) to 5 (severe/complex symptomatology). The items fall into nine

global subscales, and the scores on these subscales are summed to yield three factors;

positive, negative and disorganised. Two attentional items were excluded from the

factor score calculations as their scores do not load consistently on any of the three fac-

tors (Andreasen et al., 1995and personal correspondence with Andreasen).

2.5. Measures of cognitive functioning anduid IQ

Verbal uency was assessed using the Controlled Oral Word Association Test

(COWAT,Benton and Hamsher, 1976), in which participants are asked to produce as

many words as possible that begin with each of the letters F, A and S (with one minute

for each letter); without using proper nouns, plural words, or the same word with dif-

ferent sufxes. The dependent variable was the total number of correct words generat-

ed in response to the three letters.

The computerised spatial negative priming task was based on the paradigm used by

Park et al. (1996). Displays contained a target (letter O) and a distractor (letter X), and

there were four possible locations on the screen in which the target or distractor could ap-

pear. Each trial consisted of a prime followed by a probe display. Participants were asked to

respond only to the letter O and to ignore the X. In control trials, the locations of the targets

anddistractors in both prime andprobe displayswere different. In NP trials, thetarget in the

probe display appeared in the same position as the distractor in the prime display, and thus

participants were required to respond to the previously ignored location. The overlap be-

tween the target and distractor in the NP trials is believed to produce response retardation

since the active inhibition of ignored information during the prime display may decrease its

accessibility for later selection during the probe display (Tipper, 1985).

Participants focused on a central xation point and responded to the location of the

targetO as quickly andas accurately as possible. Responseswere made by pressing oneof

four keys on a special response box attached to the computer. Trials were initiated by

pressing the spacebar and each trial began with the presentation of the centralxation

point for 0.8 s. Theprime display was then presenteduntil participants located the target

and responded. After a further 0.5 s the central xation point appeared (again for 0.8 s)followed by the probe display which remained on the screen until a response was

made. After participants responded to the probe display, a pattern mask appeared for

1 s and then the next trial began. There were four blocks of 18 pairs of experimental tri-

als, consistingof 9 NPand 9 control trials, whichwere presented ina xed random order.

A set of 10 practice trials preceded the experimental trials.

The main dependent measure was the NP reaction time score (NPrt), which was

calculated by subtracting the mean reaction time for control probe trials from the

mean reaction time for NP probe trials. Separate mean reaction time scores for the

rst and second blocks of the task (n =36 trials in each block) were also computed

to ascertain whether any decits in performance and their corresponding schizotypal

features were specic to the initial or the latter phase of the task.

The matrices from the Wechsler Adult Intelligence Scale III (Wechsler, 1997) were

used as a brief measure of uid intelligence. In this untimed test participants were

shown a series of 26 matrices, each of which had a missing cell. For each item partici-

pants were asked to choose the correct completion from 5 options, based on the rela-

tionships (across rows and columns, etc.) for the other cells in the matrix. An initial

raw score was calculated by summing the number of correct items completed by par-ticipants (with a maximum score of 26) and the raw scores were then converted to

age-adjusted scaled scores as described in the manual.

2.6. Procedure

All participants were asked to read and sign a consent form and to provide the de-

mographic information: age, gender, number of years in education, and whether En-

glish was their native language (a binary variable coded 1= native English,

0= English not native language). In Study 1 the healthy participants were then

asked to complete the SPQ and cognitive and uid IQ tasks. One participant failed to

complete both of the cognitive tasks and two failed to complete the negative priming

task; therefore, these participants were excluded from the analyses.

In Study 2 the patientsrecords were accessed to obtain information on diagnosis,

medication and general medical history. Patients completed the SAPS/SANS interview,

followed by the cognitive tasks and WAIS-III matrices. In each of the two studies half of

the participants performed the uid IQ test before the cognitive tests and the remain-

ing participants performed the IQ test afterwards. Systematic order effects were mini-mised by also counterbalancing the order of presentation of the verbal uency and NP

tasks. On completion of the tasks all participants were debriefed, provided with a small

remuneration, and thanked for their participation.

3. Results

3.1. Study 1healthy participants

3.1.1. Data distributions and outlier removal

Scores on the SPQ and verbal uency measures were normally dis-

tributed. One outlier score was found in the overall NP index and one

in the Block 1 NP index, and two outliers were present in the Block 2

NP index. These scores were removed in order to normalise the data

distributions.

231M. Cochrane et al. / Psychiatry Research 196 (2012) 230234


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3.1.2. Descriptive statistics

Descriptives for the SPQ, cognitive and uid IQ measures are pre-

sented inTable 1. The SPQ positive factor was composed of the Unusual

PerceptualExperiences, Ideasof Reference, Odd Beliefs/Magical Thinking

and Paranoid Ideation scores, and the disorganised factor comprised the

summation of the Odd Speech and Odd/Eccentric Behaviour scores. The

negative factor was composed of the Excessive Social Anxiety, No Close

Friends and Constricted Affect scores. The internal consistency of the

SPQ subscales was assessed by coefcient alpha and the values accorded

closely with Raine's (1991) coefcients, which ranged from 0.71 to 0.78.

The mean SPQ total score of 25.0 (S.D.=13.4) was consistent with the

mean SPQ total scores of two groups of healthy participants reported

by Raine et al. (1991): 26.9 (S.D.= 11.0) and 26.3 (S.D.=11.4) in

Samples 1 and 2 respectively.

3.1.3. Correlational analyses

Bonferroni adjustments were made for multiple correlations be-

tween the personality measures, whereas the exploratory correla-

tions between uid IQ and the schizotypal personality measures,

and between the demographic and cognitive measures, were tested

at an unadjusted alpha ofP0.05. Correlations between uid IQ and

the cognitive measures were tested one-tailed, as we expected that

higher levels ofuid IQ would be associated with enhanced perfor-

mance (higher VF, increased NP) on the cognitive tasks.

3.1.3.1. Intercorrelations among the SPQ factors.The intercorrelations of

the main personality variables were assessed using 3 Pearson's

correlations and were therefore tested at an adjusted alpha of

P0.017 (~0.05/3). There was a signicant correlation between the

CognitivePerceptual factor and the Interpersonal factor (r=0.53,

Pb0.001) and between the CognitivePerceptual and Disorganised

factors (r=0.59, Pb0.001). There was also a signicant correlation

between the Interpersonal and Disorganised factors (r=0.35, Pb0.001).

3.1.3.2. Fluid IQ and schizotypy.There were no signicant relation-

ships between

uid IQ and the SPQ positive (r=

0.11), negative(r=0.10) and disorganised (r=0.08) factors (P>0.05).

3.1.3.3. Fluid IQ and cognitive task performance.Fluid IQ was signi-

cantly positively associated with verbal uency (r=0.42, Pb0.001)

and with performance in Block 1 of the NP task ( r=0.18, P=0.04,

1-tailed). However, there was no signicant correlation between

uid IQ and the overall NP index (r=0.06), or the Block 1 NP

index (r=0.03) (P>0.05).

3.1.3.4. Demographic variables and cognitive task performance. There

were no signicant relationships between the demographic and

cognitive measures (P>0.05).

3.2. Multiple regression analyses

Four standard multiple regressions were conducted to assess the

independent contribution of the personality measures to the predic-

tion of each cognitive (dependent) measure. Fluid IQ was added to

the regressions assessing VF and Block 1 NP, as was the language var-

iable, which was signicantly positively correlated with VF (r=0.37,

Pb0.001) and Block 1 NP (r=0.21, Pb0.05). Negative and disorga-

nised schizotypal features as predictors of VF and NP respectively

were tested one-tailed, given the direction of the effects reported in

previous research. The independent contribution of uid IQ to the

prediction of cognitive task performance was also tested one-tailed.

Positive schizotypal features were tested as predictors two-tailed

given the occasional report of an effect in the opposite direction to

the majority of effects (Tsakanikos and Claridge, 2005). The resultsof the regression analyses are shown inTable 2.

3.2.1. Verbal uency

The SPQ factors, uid IQ and language were used as predictors,

with the number of words generated in the VF task as the dependent

variable. There was a near-signicant trend for a negative effect of

SPQ negative schizotypy (=0.17, Pb0.06, one-tailed), over and

above the robustly signicant independent contributions ofuid IQ

(=0.33,Pb0.001) and English as rst language (=0.34,Pb0.001).

3.2.2. Negative priming (NP)

Regression analysis with the SPQ factors as predictors of the over-

all NP reaction time index revealed that higher levels of disorganised

Table 1

Descriptives for the personality and cognitive measuresStudy 1.

Mean (S.D.) Min Max N Alpha

SPQ factors

Positive (cognitiveper ceptual) 11.14 ( 7.15) 0.00 30.00 99 0.89

Negati ve (interpersonal) 6.98 (5.08) 0.00 22.00 100 0.86

Disorganisation 7.00 (4.07) 0.00 14.00 99 0.85

SPQ subscales

Ideas of reference 3.94 (2.60) 0.00 9.00 100 0.77Odd beliefs/magical t hinking 2.26 ( 2.18) 0.00 7.00 100 0.81

Unusual perceptual experiences 2.49 (2.36) 0.00 9.00 99 0.77

Paranoid ideation 2.55 (2.26) 0.00 8.00 100 0.78

Excessi ve social anxiety 3.00 (2.29) 0.00 8.00 100 0.77

No close friends 2.06 (2.03) 0.00 9.00 100 0.72

Constricted affect 1.92 (1.65) 0.00 6.00 100 0.61

Odd or eccentric behavior 2.60 (2.19) 0.00 7.00 99 0.82

Odd speech 4.141 (2.49) 0.00 8.00 100 0.76

Cognitive measures

Verbaluency 40.78 (11.29) 13.00 73.00 99

Negative priming (NP) 0.02 (0.05) 0.27 0.08 98

Block 1 NP 0.00 (0.05) 0.19 0.13 97

Block 2 NP 0.01 (0.04) 0.12 0.11 96

Fluid IQ 14.10 (2.15) 9.00 19.00 99

Table 2

Predictors of executive functioningStudy 1.

Dependent measures

Verbaluency Negative priming Block 1 negative priming Block 2 negative priming

Predictors B SEB B SEB B SEB B SEB

Fluid IQ 1.752 0.473 0.334*** 0.004 0.002 0.173*

Language 8.405 2.238 0.341*** 0.020 0.011 0.182

SPQ pos 0.069 0.197 0.043 0.001 0.001 0.247 0.001 0.001 0.162 0.002 0.001 0.251

SPQ neg 0.373 0.233 0.167 0.001 0.001 0.107 0.000 0.001 0.057 0.001 0.001 0.069

SPQ disorg 0.021 0.308 0.008 0.002 0.001 0.244* 0.000 0.002 0.031 0.005 0.001 0.428***

R2=0.296, adjR2=0.258

(F(5, 92)=7.728, Pb0.001)

R2=0.050, adjR2=0.020

(F(3, 93)=1.647,ns)

R2=0.084, adjR2=0.033

(F(5, 90)=1.658,ns)

R2=0.121, adjR2=0.093

(F(3, 92)=4.236, Pb0.01)

Note: SPQ Pos = SPQ CognitivePerceptual (positive) factor; SPQ Neg = SPQ Interpersonal (negative) factor; SPQ Disorg = SPQ Disorganisation factor.

*P

0.05, ***P

0.001, trend effect (Pb

0.06).

232 M. Cochrane et al. / Psychiatry Research 196 (2012) 230234


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schizotypy signicantly predicted reduced negative priming (=

0.24,Pb0.03, 1-tailed). There was weak trend (=0.25,Pb0.08,

2-tailed) for a positive association between negative priming per-

formance and positive schizotypy, while the negative schizotypal

factor did not signicantly contribute to the variance in NP.

When the SPQ factors, uid IQ and language were used as predic-

tors of the NP reaction time index in the rst block of the task,uid IQ

was the only signicant predictor of (greater) NP (=0.17,P = 0.05,

1-tailed). When the SPQ variables were used as predictors of NP per-formance in the second block of the task, positive schizotypy again

tended to predict greater negative priming (=0.25, Pb0.07, 2-

tailed); however, disorganised schizotypy independently and signi-

cantly predicted reduced negative priming (=0.43,Pb0.001, 1-

tailed).

3.3. Study 2patients with schizophrenia

3.3.1. Descriptive statistics

Scores on the symptom and cognitive task measures were normal-

ly distributed. The descriptives are shown inTable 3.

3.3.2. Correlational analyses

The analyses were conducted in accordance with Study 1. Pear-

son's correlations used to assess the relationships between the symp-

tom and demographic measures were tested two-tailed and were

non-signicant (P>0.05). The correlations between uid IQ and the

cognitive measures were tested one-tailed. There were no signicant

correlations between the uid IQ measure and the negative priming

indices; however, there was a trend for a positive relationship be-

tweenuid IQ and VF (r=0.35,P=0.06).

The relationships between the SAPS/SANS scores and cognitive

task performance were tested one-tailed for negative and disorga-

nised schizotypy and two-tailed for positive schizotypy. The negative

factor scores were signicantly negatively associatedwithVF (r=0.43,

P=0.03, 1-tailed) and the disorganised factor scores were signicantly

negatively associated with NP (r=0.53,Pb0.01, 1-tailed). The signi-

cant association between disorganised symptomatology and negative

priming was specic to performance in the latter phase of the task(r=0.51, P=0.01, 1-tailed) as opposed to the initial phase (r=

0.27, P=0.13, 1-tailed); the same pattern that was found in the

healthy participants with SPQ disorganised schizotypy in Study 1.

There were no signicant correlations between the positive factor

scores and the cognitive measures.

3.3.3. Multiple regression analysis

Given the trend for a positive association between VF and uid IQ,

and the robust and signicant positive correlation between these var-

iables in the larger sample of healthy participants, VF was reanalysed

in a regression using both SANS negative factor score and uid IQ as

predictors. This reduced the independent prediction of VF by SANS

negative factor score to a near-signicant trend (=0.36,Pb0.06,

1-tailed), while the independent prediction of VF by uid IQ was

non-signicant (=0.27, P=0.12, 1-tailed). (R2 =0.25, Adj. R2 =

0.16,F(2, 17)=2.80,P>0.05).

4. Discussion

In accordance with expectations, high levels of negative schizo-

typy predicted reduced verbal uency and high levels of SPQ disorga-

nised schizotypy predicted reduced negative priming in the healthyparticipants in Study 1. This latter effect was particularly evident in

the second block of the NP task. It seems that for participants high

in disorganisation, inhibitory processing was initially intact, but a dif-

culty in sustaining this ability was evident as the task progressed.

Higher levels of SPQ positive schizotypy tended to predict enhanced

inhibition in the latter part of the NP task; a nding which is at

odds with other published NP results showing a negative relationship

(Peters et al., 1994; Park et al., 1996) and therefore may require fur-

ther investigation to determine if it is replicable. This direction of ef-

fect has been previously reported for the inuence of positive

schizotypy on VF (Tsakanikos and Claridge, 2005); however, no

such effect was observed in the present study.

Study 2 examined the pattern of relationships between clinical

symptomatology and cognitive task performance in patients with

schizophrenia and revealed the same pattern of relationships. Higher

levels of disorganised symptoms were signicantly associated with

reduced negative priming, and this relationship was specic to the

second phase of the task. Higher levels of negative symptoms were

signicantly correlated with reduced verbal uency; however, the

prediction of VF by negative symptomatology was slightly reduced

in a regression controlling for uid IQ. Nevertheless, on both tasks,

continuity was observed across the groups of patients and healthy

participants.

The association between negative symptomatology and verbal u-

ency is consistent with previous research in patient groups ( Liddle

and Morris, 1991; Frith, 1992) and in schizotypal participants

(Tsakanikos and Claridge, 2005). The relationship between SAPS dis-

organisation and reduced NP in patients with schizophrenia corre-

sponds with that reported by Williams (1996). However, theassociation between disorganisation and reduced NP in the schizoty-

pal individuals does not accord with other reported relationships

which have emphasised the link between positive schizotypy and re-

duced NP. This discrepancy cannot be fully explained by the NP tasks

used in the different studies:Peters et al. (1994)used a Stroop-based

task but Park et al. (1996) used a spatial NP task, on which the current

task was closely based. The inconsistency across studies could arise

from the use of different schizotypy inventories: while Park et al.

and Peters et al. used the Perceptual Aberration Scale (PAS,

Chapman et al., 1978) and Combined Schizotypal Traits Questionnaire

(CSTQ,Claridge et al., 1996) respectively, the current schizotypy/NP

relationship was found using the SPQ. Interestingly, the relationship

between disorganised schizophrenia and NP found in this study and

byWilliams (1996)was obtained using the same instrument (SAPS/SANS). It may be difcult to clearly delineate the pattern of relation-

ships between symptomatology and cognition when methods of

assessing these phenomena are so varied.

The inclusion of the uid IQ measure in these studies was impor-

tant in highlighting the contribution of this process to cognitive task

performance, and in demonstrating that uid IQ did not fully account

for variations in performance. Fluid IQ may be regarded as a key com-

ponent of cognitive functioning (Duncan, 1995) and yet the ability of

schizophrenic symptomatology and schizotypal personality to predict

residual variance in verbal uency, after accounting for the contribu-

tion ofuid IQ, was established. Fluid IQ made no signicant contri-

bution to the prediction of negative priming in the patients with

schizophrenia, but did contribute to the variance in Block 1 NP in

the healthy participants.

Table 3

Descriptives for the cognitive measures and uid IQStudy 2.

Mean (S.D.) Min Max N

Symptom measures (SAPS/SANS)

Positive factor 5.05 (2.91) 0.00 9.00 20

Negative factor 9.05 (3.58) 1.00 15.00 20

Disorganised factor 1.90 (1.86) 0.00 6.00 20

Cognitive measures

Verbaluency 34.80 (8.57) 17.00 46.00 20

Negative priming 0.01 (0.13) 0.47 0.26 20

Block 1 NP 0.03 (0.12) 0.11 0.47 20

Block 2 NP 0.04 (0.21) 0.91 0.76 20

Fluid IQ 10.85 (2.28) 6.00 16.00 20

233M. Cochrane et al. / Psychiatry Research 196 (2012) 230234


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Our ndings are interpreted with some caution since we did not

provide a formal assessment of some factors which may have impacted

on the relationships observed between symptomatology and cognitive

task performance. In Study 1 we did not have a formalised list of cri-

teria for establishing a serious physical medical condition, nor did

we perform any diagnostic assessment of psychopathology in the

healthy participants; rather, in both instances, the data were obtained

by means of self-report to general questions regarding these criteria.

In the patient group in Study 2 we did not include an assessment ofthe class or dosage of atypical antipsychotic medication and therefore

could not statistically assess potential effects of medication. Further-

more, multiple regression analysis with SANS negative symptomatolo-

gy anduid IQ as predictors of verbaluency was conducted with low

power in such a small sample (n =20).

It could be argued that the lack of a control group is also a limita-

tion of Study 2. However, we do not regard this as a serious issue as

the research here is concerned with the relationships between symp-

toms and cognitive measures within a patient sample. The current re-

search questions are largely unaffected by whether the schizophrenic

group is signicantly impaired on a particular cognitive measure. If VF

(or NP) relate to a specic class of symptoms, then whether the par-

ticular schizophrenic sample, as a whole, is impaired with respect to

an appropriate matched control group will depend on the level of

the relevant symptom type: if it is high then the group will be im-

paired as a whole, if it is low, then the group might well not show

an impairment.

In conclusion, this is the rst report of a consistent pattern of

symptom-cognition relationships across a group of patients with

schizophrenia and a large group of healthy participants. For these

two specic relationships we thus provide convincing evidence for

the continuum model; demonstrating not only that schizophrenia-

like traits are present in the healthy population but also showing

that these traits may lead to disruptions in cognitive performance in

patients and schizotypal individuals in a similar manner. Future stud-

ies may be further informed by the inclusion of multiple measures of

cognition and additional culture-fair measures of general/uid

intelligence.

References

American Psychiatric Association, 1987. Diagnostic and Statistical Manual of MentalDisorders, 3rd edition revised. APA Press, Washington.

Andreasen, N.C.,1983. The Scale for the Assessment of NegativeSymptoms (SANS). TheUniversity of Iowa, Iowa City.

Andreasen, N.C., 1984. The Scale for the Assessment of Positive Symptoms (SAPS). TheUniversity of Iowa, Iowa City.

Andreasen, N.C., Arndt, S., Alliger, R., Miller,D., Flaum, M., 1995. Symptoms of schizophrenia:methods, meanings and mechanisms. Archives of General Psychiatry 52, 341351.

Barrantes-Vidal, N., Fananas, L., Rosa, A., Caparros, B., Riba, M.D., Obiols, J.E., 2003.Neurocognitive, behavioural and neurodevelopmental correlates of schizotypyclusters in adolescents from the general population. Schizophrenia Research 61,293302.

Baving, L., Wagner, M., Cohen, R., Rockstroh, B., 2001. Increased repetition and semanticpriming in schizophrenic patients. Journal of Abnormal Psychology 110, 6775.

Beech, A., Powell, T., McWilliam, J., Claridge, G., 1989. Evidence of reduced cognitiveinhibitionin schizophrenia. British Journal of Clinical Psychology 28, 109116.

Benton, A.L., Hamsher, K.deS, 1976. Multilingual Aphasia Examination. University ofIowa, Iowa City.

Chapman, L.J., Chapman, J.P., Raulin, M.L., 1978. Body-image aberration in schizophrenia.

Journal of Abnormal Psychology 86, 399407.Claridge, G., Beech, T., 1995. Fully and quasi-dimensional constructions of schizotypy.In: Raine, A., Lencz, T., Mednick, S.A. (Eds.), Schizotypal Personality. CambridgeUniversity Press, Cambridge, pp. 192216.

Claridge, G., McCreery, C., Mason, O., Bentall, R., Boyle, G., Slade, P., Popplewell, D.,1996. The factor structure ofschizotypal traits: a large replication study. British

Journal of Clinical Psychology 35, 103115.Diforio, D., Walker, E.F., Kestler, L.P., 2000. Executive functions in adolescents with

schizotypal personality disorder. Schizophrenia Research 42, 125134.Duncan, J., 1995. Attention, intelligence, and the frontal lobes. In: Gazzaniga, M.S. (Ed.),

The Cognitive Neurosciences. MIT Press, Cambridge, MA, pp. 721733.Franke, P., Maier, W., Hardt, J., Hain, C., 1993. Cognitive functioning and anhedonia in

subjects at risk for schizophrenia. Schizophrenia Research 10, 7784.Frith, C.D., 1992. The Cognitive Neuropsychology of Schizophrenia. Psychology Press,

East Sussex.Laplante, L., Everett, J., Thomas, J., 1992. Inhibition through negative priming with

Stroop stimuli in schizophrenia. British Journal of Clinical Psychology 31, 307326.Liddle, P.F., Morris, D.A., 1991. Schizophrenic syndromes and frontal lobe performance.

The British Journal of Psychiatry 158, 340345.

Moritz, S., Ruff, C., Wilke, U., Andresen, B., Krausz, M., Naber, D., 2001. Negative primingin schizophrenia: effects of masking and prime presentation time. SchizophreniaResearch 48, 291299.

Park, S., Lenzenweger, M.F., Puschel, J., Holzman, P.S., 1996. Attentional inhibition inschizophrenia and schizotypy: a spatial negative priming study. CognitiveNeuropsychiatry 1 (2), 125149.

Peters, E.R., Pickering, A.D., Hemsley, D.R., 1994. Cognitive inhibition and positivesymptomatology in schizotypy. British Journal of Clinical Psychology 33, 3348.

Peters, E., Pickering, A., Kent, A., Glasper, A., Irani, M., Day, S., David, A., Hemsley, D.,2000. The relationship between cognitive inhibition and psychotic symptoms.

Journal of Abnormal Psychology 109, 386395.Raine, A., 1991. The SPQ: a scale for the assessment of schizotypal personality based on

DSM-III-R criteria. Schizophrenia Bulletin 17, 555564.Raine, A., Reynolds, C., Lencz, T., Scerbo, A., Triphon, N., Kim, D., 1991. Cognitiveperceptual,

interpersonal, and disorganised features of schizotypal personality. SchizophreniaBulletin 20 (1), 191201.

Ruiz, M.C.A., Barrantes-Vidal, N., Guitart, M., Fananas, L., 2008. Study of neurocognitivecorrelates of schizotypy personality clusters in healthy individuals. European Journalof Psychiatry 22 (1), 1728.

Tipper, S., 1985. The negative priming effect: inhibitory priming by ignored objects.Quarterly Journal of Experimental Psychology 37A, 571590.

Tsakanikos, E., Claridge, G., 2005. Less words, more words: verbal uency as a functionofpositive and negative schizotypy. Personality and Individual Differences 39,705713.

Wechsler, D., 1997. Wechsler Adult Intelligence Scale III. Manual for Administrationand Scoring. David Wechsler Corporation. Harcourt Brace & Co, San Antonio.

Williams, L.M., 1996. Cognitive inhibition and schizophrenic symptom subgroups.Schizophrenia Bulletin 22, 139151.

234 M. Cochrane et al. / Psychiatry Research 196 (2012) 230234

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