emotional stroop performance predicts disorganization in schizophrenia

9
Emotional Stroop performance predicts disorganization in schizophrenia Laura K. Phillips a, T , Patricia J. Deldin b , Martina M. Voglmaier c , Sarah Rabbitt d a Department of Psychology, Harvard University, 33 Kirkland Street Rm. 1205, Cambridge, MA, 02138, USA b Department of Psychology, University of Michigan, Ann Arbor, 525 E. University, 2252 East Hall, Ann Arbor, MI, 48109, USA c Department of Psychiatry, Harvard Medical School, Cambridge Health Alliance, 1493 Cambridge St., Cambridge, MA 02139, USA d Clinical and Research Program in Pediatric Psychopharmacology, Massachusetts General Hospital, 185 Alewifebrook Parkway, Cambridge, MA 02138 USA Received 29 October 2004; received in revised form 6 February 2005; accepted 16 February 2005 Available online 1 April 2005 Abstract An examination of emotional processing in individuals with schizophrenia may aid in understanding the heterogeneous disease states of schizophrenia. An emotional Stroop test, comprising conditions separated by both emotional valence (positive, negative) and arousal (low, high), was administered to disorganized (N = 12) and non-disorganized (N = 15) schizophrenic and schizoaffective participants, and 22 non-patient controls. Results indicate that the performance of disorganized versus non- disorganized participants differed particularly on the negative, high arousal condition. Understanding which symptom dimensions accompany aberrant emotion processing might be useful in understanding the mechanisms involved in the exacerbation of symptoms, particularly disorganization. Such information may lead to improved treatment and prevention strategies for schizophrenia spectrum diagnoses. D 2005 Elsevier B.V. All rights reserved. Keywords: Disorganization; Schizophrenia; Stroop; Emotion 1. Introduction Rather than comprising a single disease entity, schizophrenia may be a cluster of heterogeneous syndromes that differ in underlying structure (e.g., Andreasen et al., 1995). Efforts have been made toward the clarification of subtypes, encompassing more homogenous manifestations of the illness and perhaps common pathophysiology. At the descriptive level, the positive and negative symptom dimensions of schizo- phrenia can be broken down further into three syndromes. Negative symptoms, such as affective flattening, withdrawal, and avolition are included in a bpsychomotor povertyQ dimension. Positive symptoms can be divided into breality distortion,Q comprising 0920-9964/$ - see front matter D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.schres.2005.02.009 T Corresponding author. Tel.: +1 617 496 8563; fax: +1 617 495 3728. E-mail address: [email protected] (L.K. Phillips). Schizophrenia Research 77 (2005) 141 – 149 www.elsevier.com/locate/schres

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www.elsevier.com/locate/schres

Schizophrenia Research

Emotional Stroop performance predicts

disorganization in schizophrenia

Laura K. Phillipsa,T, Patricia J. Deldinb, Martina M. Voglmaierc, Sarah Rabbittd

aDepartment of Psychology, Harvard University, 33 Kirkland Street Rm. 1205, Cambridge, MA, 02138, USAbDepartment of Psychology, University of Michigan, Ann Arbor, 525 E. University, 2252 East Hall, Ann Arbor, MI, 48109, USA

cDepartment of Psychiatry, Harvard Medical School, Cambridge Health Alliance, 1493 Cambridge St., Cambridge, MA 02139, USAdClinical and Research Program in Pediatric Psychopharmacology, Massachusetts General Hospital,

185 Alewifebrook Parkway, Cambridge, MA 02138 USA

Received 29 October 2004; received in revised form 6 February 2005; accepted 16 February 2005

Available online 1 April 2005

Abstract

An examination of emotional processing in individuals with schizophrenia may aid in understanding the heterogeneous

disease states of schizophrenia. An emotional Stroop test, comprising conditions separated by both emotional valence (positive,

negative) and arousal (low, high), was administered to disorganized (N =12) and non-disorganized (N =15) schizophrenic and

schizoaffective participants, and 22 non-patient controls. Results indicate that the performance of disorganized versus non-

disorganized participants differed particularly on the negative, high arousal condition. Understanding which symptom

dimensions accompany aberrant emotion processing might be useful in understanding the mechanisms involved in the

exacerbation of symptoms, particularly disorganization. Such information may lead to improved treatment and prevention

strategies for schizophrenia spectrum diagnoses.

D 2005 Elsevier B.V. All rights reserved.

Keywords: Disorganization; Schizophrenia; Stroop; Emotion

1. Introduction

Rather than comprising a single disease entity,

schizophrenia may be a cluster of heterogeneous

syndromes that differ in underlying structure (e.g.,

0920-9964/$ - see front matter D 2005 Elsevier B.V. All rights reserved.

doi:10.1016/j.schres.2005.02.009

T Corresponding author. Tel.: +1 617 496 8563; fax: +1 617 495

3728.

E-mail address: [email protected] (L.K. Phillips).

Andreasen et al., 1995). Efforts have beenmade toward

the clarification of subtypes, encompassing more

homogenous manifestations of the illness and perhaps

common pathophysiology. At the descriptive level, the

positive and negative symptom dimensions of schizo-

phrenia can be broken down further into three

syndromes. Negative symptoms, such as affective

flattening, withdrawal, and avolition are included in a

bpsychomotor povertyQ dimension. Positive symptoms

can be divided into breality distortion,Q comprising

77 (2005) 141–149

L.K. Phillips et al. / Schizophrenia Research 77 (2005) 141–149142

hallucinations and delusions, and bdisorganization,Qdescribing attentional, conceptual, and behavioral

disorganization (see Liddle, 1987; Andreasen et al.,

1995, for review).

A number of theorists have attempted to refine the

construct of disorganization. Based on the results of

semantic priming studies, disorganization has been

explained as a deficit in the ability to integrate

contextual information (Hardy-Bayle et al., 2003)

and in the capacity to maintain a mental set (Rosenthal

et al., 1960). In addition, the phenomena associated

with disorganization have been explained by deficits

in working memory (Daban et al., 2003), sensory

motor ability, IQ (Basso et al., 1998), selective

attention (Ngan and Liddle, 2000), and theory of

mind (Hardy-Bayle et al., 2003). Lastly, individuals

diagnosed with higher levels of disorganization have

displayed higher levels of arousal (Lapidus and

Schmolling, 1975) and emotional reactivity (Bur-

bridge and Barch, 2002).

Evidence for the last relationship, between the

disorganization syndrome and abnormalities of

arousal and emotional reactivity, is becoming increas-

ingly evident. Docherty et al. (1994) categorize

individuals as affectively reactive if they produce

more speech errors, in the form of referential

communication failure, when discussing affectively

negative topics than when discussing affectively

positive topics. This disruption in language produc-

tion is speculated to reflect a differential responsivity

to negative valence (Docherty et al., 1994). Specifi-

cally, language reactivity, during the discussion of

stressful events, is greater in participants who scored

higher on positive symptoms (includes both the

positive and disorganization dimensions) (Docherty

and Herbert, 1997), while unrelated to deficit symp-

toms (Cohen and Docherty, 2003). Similarly, Bur-

bridge and Barch (2002) found that symptoms under

the disorganization dimension predicted affective

reactivity in language. Finally, in a study where

individuals with schizophrenia rated slides on pleas-

antness and arousal, higher levels of disorganization

was associated with lower ratings on the pleasant

slides and with a more negative mood post study

participation (Quirk et al., 1998). Thus, both aberrant

emotional processing and emotional reactivity may be

characteristic of individuals meeting criteria for the

disorganized dimension of schizophrenia.

1.1. The emotional Stroop

In the current study, we examined whether aberrant

emotional processing is evident in individuals with

schizophrenia or schizoaffective disorder who score

higher on levels of disorganization. Specifically, we

compared the emotional Stroop performance of those

within the schizophrenia spectrum group who scored

higher in disorganization with those who scored

lower. The emotional Stroop is a variant of the

standard color Stroop (see Williams et al., 1996, for

review). In this task, words with positive or negative

emotional valence are printed in colored ink, and the

participant is asked to name the color of the word

while attempting to ignore the meaning of the word.

Interference is measured by the delay in response time

and errors in naming the color of the word. Increased

response time in color naming reflects increased

attention allocated toward the meaning of the word,

as well as difficulty disengaging attention from it.

Few studies have examined emotional Stroop

effects in schizophrenia, and none has specifically

addressed the Stroop in the disorganized subtype. This

is a surprising oversight given that a possible

dysfunctional affective system, as suggested by the

associated differential responsivity to negative

valence (as cited above), may be more likely to be

associated with aberrant processing on this task.

Epstein et al. (1999) employed an emotional Stroop

test to measure responsivity to threatening verses

neutral information. Although controls showed

increased mesolimbic activity to threat but not neutral

stimuli, individuals with schizophrenia showed

increased mesolimbic activity in both threatening

and neutral contexts, reflecting heightened responsiv-

ity to neutral information. Bentall and Kaney (1989)

found that individuals with persecutory delusions

showed an increased response time to words with

hostile content versus neutral words. Thus, it remains

unclear whether a Stroop effect in schizophrenia is an

effect of emotionality, negativity, arousal, or specific

to hostile information.

1.2. Purpose of the current study

The purpose of the current study was to determine

whether the disorganization symptom dimension is

associated with abnormalities in emotional Stroop

Table 1

Demographic and clinical characteristics

Characteristic Control group Patient group

Mean (SD) Mean (SD) t p

Gender 11 F; 11 M 13 F; 19 M x2=1.85 .933

Age 42.16 (9.06) 37.79 (12.12) 1.36 .342

Education

(in years)

16.86 (1.83) 13.14 (2.30) 6.31 b .01

Wechsler test

of adult reading

41.9 (8.96) 31.4 (8.82) 4.27 b .01

Age of onset

(in years)

20.50 (3.08)

Length of illness

(in years)

22.94 (9.45)

Taking atypical

antipsychotics

(%)

72

Taking typical

antipsychotics

(%)

26

Taking

antiparkinsonians

(%)

15

L.K. Phillips et al. / Schizophrenia Research 77 (2005) 141–149 143

performance. Further, we aimed to disentangle res-

ponsivity to valence from that of arousal to determine

which specific components of emotion are most

related to disorganization. It is unknown whether

individuals with schizophrenia process arousal differ-

ently, regardless of valence; or if instead, they process

valence differently, regardless of the level of the

arousal of the stimulus. Although past work (cited

above) has shown that individuals with schizophrenia

as a group show increased interference with threat

related words, relative to neutral words, no work to

date involving the Stroop and schizophrenia has

examined the effect of more generally positively and

negatively valenced emotional stimuli, separated by

level of arousal. Further, no study has addressed group

differences, defined by level of disorganization on an

emotional Stroop task.

1.3. Hypotheses

Quirk et al. (1998) showed that disorganized

schizophrenics interpreted negative stimuli as more

salient than positive stimuli compared to non-disor-

ganized schizophrenics. Based on these findings, we

hypothesized that individuals with a schizophrenic

disorder who were more disorganized would display

increased attention allocated to the content of the

negative words relative to words that were positive in

content. Specifically, we predicted that individuals

diagnosed with a schizophrenic disorder who show

higher levels of disorganization, relative to those with

lower levels of disorganization, would show longer

response time and decreased accuracy in the neg-

atively valenced, high arousal condition, relative to

the neutral condition.

Taking

antidepressants

(%)

41

Taking

moodstabilizers

(%)

18

Taking

benzodiazepines

(%)

15

PANSS

Reality disortion 7.37 (1.76)

Poverty

symptoms

5.74 (2.36)

Disoganization 10.48 (2.90)

Total 68.96 (11.37)

2. Methods

2.1. Participants

The group consisting of individuals diagnosed with

schizophrenia (SZ) or schizoaffective disorder (SA)

included 32 (18 SZ [13 males and 5 females] and 14

SA [6 males and 8 females]) individuals who met

DSM-IV criteria. These participants were recruited

through newspaper advertisements and flyers,

announcing a study looking for individuals with

diagnoses of schizophrenia or schizoaffective disor-

der. A phone screen served as a preliminary test for

study eligibility. A doctoral-level clinical psychologist

(PJD) or a trained clinical psychology graduate

student used the Structured Clinical Interview for

the DSM-IVAxis I Disorders Patient Edition (SCID-I/

P: First et al., 1995) to interview all participants. All

subjects were right handed as determined by the

Annett Handedness Inventory (Annett, 1970). The

demographic variables collected include: gender, age,

and education (Table 1). Reading ability, relative to

other cognitive domains, is presumed to be less

affected by the pathophysiology associated with

schizophrenia; thus, the WTAR was also administered

L.K. Phillips et al. / Schizophrenia Research 77 (2005) 141–149144

because of its utility as a measure of potential IQ

(Ginsberg, 2003).

Per participant report, all but one of the individuals

diagnosed with schizophrenia or schizoaffective dis-

order were taking psychotropic medication (twenty-

eight individuals on atypical antipsychotics, ten on

typical neuroleptics, six on benzodiazepines, sixteen

on antidepressants, six on antiParkinsonian agents,

and seven were taking a mood stabilizer, Table 1). The

schizophrenia/schizoaffective group experienced a

mean age of onset of 20.50 years (SD=3.08) and an

average duration of illness of 22.9 years (SD=9.45).

All interviews were audiotaped and administered with

2 interviewers present who came to a consensus on all

clinical ratings.

A median split was used to divide those individuals

diagnosed with schizophrenia and schizoaffective

disorder, who scored higher on the disorganization

cluster of the Positive and Negative Symptom Scale

(PANSS; Kay et al., 1987), from those who scored

relatively lower. These two groups (disorganized,

n =12; non-disorganized, n =15) differed significantly

on all four items of disorganization (F =10.7,

p b .001, eta = .81), conceptual disorganization

( p b .01) mannerisms and posturing ( p b .01), diffi-

culty in abstract thinking ( pb .01), and poor attention

( p b .01). The two groups did not differ on any of the

demographic variables [gender ( p = .93), age

( p =.34), education ( p =.80), WTAR ( p =.61), diag-

nosis ( p =.62), duration of illness ( p= .16), age of

onset ( p =.94), medication status ( p =.39), or type of

antipsychotic medication (typical versus atypical)

( p =.21)].

The control group consisted of twenty-two partic-

ipants (11 males and 11 females), who were recruited

through newspaper advertisements and flyers in the

Boston area. They were interviewed, with the use of the

SCID, by the same clinician and graduate students.

There were no significant differences between the

groups on gender and age, and all subjects were right

handed as determined by the Annett Handedness

Inventory (Annett, 1970). However, individuals in the

schizophrenia/schizoaffective group, on average,

experienced fewer years of education and had lower

WTAR scores compared to those in the control group.

Exclusionary criteria, for both groups, included:

learning disabilities, head injuries resulting in loss of

consciousness for more than 10 min, anorexia

nervosa, seizure disorders, and other primary neuro-

logical disorders. Additional criteria for the control

group included no current or past history of Axis I

psychiatric disorder. The group with schizophrenia

disorders had no other history of Axis I mood

disorder.

All study procedures were approved by the

Harvard Institutional Review Board. The details of

the study were explained to all participants, and after

all questions were addressed, written informed con-

sent was obtained. Participants were compensated US

$10 for each hour of their participation.

2.2. Procedures

2.2.1. Questionnaires

After establishment of each participant’s eligibil-

ity, we administered the Positive and Negative

Symptom Scale (PANSS; Kay et al., 1987), the

Annett Handedness Inventory (Annett, 1970), and

the Wechsler Test of Adult Reading (WTAR: The

Psychological Corporation, 2001). The PANSS varia-

bles were divided into three symptom clusters:

reality distortion, poverty symptoms, and disorgani-

zation (similar to Liddle, 1987; Burbridge and Barch,

2002). Reality distortion included delusions and

hallucinations. Poverty symptoms included blunted

affect, motor retardation, and lack of spontaneity.

Disorganization encompassed conceptual disorgani-

zation, mannerisms and posturing, difficulty in

abstract thinking, and poor attention.

2.2.2. Emotional Stroop color-naming paradigm,

modified

Participants were presented with five blocks of 15

words from the Affective Norms for English Words

(ANEW) list (Bradley and Lang, 1999). Words were

displayed in four different colors: blue, red, green,

and brown. The specific colors were selected

because each contains only one syllable. Participants

were instructed to name the color of the ink of the

words as quickly as possible. The conditions differed

by valence and arousal (see Appendix for word list),

consisting of words that were: neutral (e.g., constant);

negative, low arousal (e.g., weak); positive, low

arousal (e.g., sincere); negative, high arousal (e.g.,

furious); and positive, high arousal (e.g., ecstatic). The

conditions appropriately differed according to ratings

L.K. Phillips et al. / Schizophrenia Research 77 (2005) 141–149 145

of valence and arousal and were matched on

frequency and length. Valence and arousal ratings,

taken from the ANEW word list, were on a scale of 1–

5, with 1 being the most positive and of the highest

arousal (neutral: valence=2.94, arousal=3.41; nega-

tive low: valence=4.06, arousal=3.30; positive low:

valence=1.84, arousal=3.13; negative high: valence=

4.22, arousal=2.01; and positive high: valence=1.73,

arousal=1.91).

Each block consisted of 2 practice stimuli followed

by 60 scored stimuli presented on an Apple Macin-

tosh. A word was never repeated more than once. A

custom-made program, through the use of SuperLab,

controlled the interstimulus interval. Each word

remained on the screen until the participant

responded, with a 1000 ms interval between the

participant’s response and the next stimulus presenta-

tion. Automatic collection of response times was

performed through a computer microphone with a

voice-activated trigger. We used Adobe Photoshop to

create stimuli in the font Times, 150 pixels. Partic-

ipants pressed the space bar to initiate the presentation

of stimuli. The vocal responses were manually

recorded by the experimenter with the use of a list

of correct responses, and the participants’ vocal

responses were tape-recorded to ensure accuracy of

coding. Blocks, word order, and color of words were

pseudo-randomly counterbalanced with the following

restrictions: the neutral condition occurred in an equal

number of times in each of the five possible order

positions and the color of the words was never

repeated more than 3 times in succession.

2.3. Data analyses, scoring of the emotional Stroop

First, difference scores were obtained by subtract-

ing the response time to the neutral Stroop condition

from those of each of the emotional Stroop conditions

A repeated measures multivariate analysis of variance

(MANOVA) was performed, with diagnosis (schizo-

phrenia, schizoaffective, control) as the between

subjects factor and valence (positive, negative) and

arousal (low, high) as within subjects factors, in order

to determine if there were any differences among the

three diagnostic groups. This was followed by

pairwise comparisons to assess differences between

the two psychiatric groups to ensure that diagnosis

was not a confound of any group differences between

those individuals who are more versus less Disor-

ganized. Correlations among each of the four emo-

tional Stroops and each of the symptom clusters

(reality distortion, poverty symptoms, and disorgani-

zation) were examined.

A repeated measure multivariate analysis of

variance (MANOVA), with group (disorganized,

non-disorganized) as the between subjects factor and

response time to valence (positive, negative) and

arousal (low, high) as within subjects factors, was

performed to examine valence versus arousal affects

between the groups. This was followed by planned

comparisons, in order to examine differences between

the groups (disorganized, non-disorganized) in

response time to each of the emotional Stroop

conditions (negative valence, low arousal; negative

valence, high arousal; positive valence, low arousal;

positive valence, high arousal). The above analyses

were repeated for accuracy data, where an error

equaled reading the actual word (rather than naming

its color) or naming the color incorrectly. Lastly, a

binary stepwise logistic regression analysis was

performed to determine if response times on the

emotional Stroop conditions could correctly classify

those with the highest scores on the disorganization

dimension from those with the lowest.

3. Results

Although there were no significant differences

among the three diagnostic groups (schizophrenia,

schizoaffective, control) (p=.09) or between the two

psychiatric groups on any of the emotional Stroop

conditions, significant differences emerged in response

time to emotional stimuli between those individuals who

scored higher on levels of disorganization and thosewho

scored lower (Fig. 1). Response time to the negative,

high arousal condition correlated with the dimension of

disorganization (r=.47, p=.02); neither reality distor-

tion nor poverty symptoms correlated with any of the

emotional Stroop conditions. The repeated measures

analysis revealed that group differences existed across

both valence and arousal. When the conditions were

collapsed across levels of arousal, those who scored

higher on disorganization showed increased response

times for negative and decreased response times for

positive blocks, relative to those who showed lower

-80

-40

0

40

80

Non-Disorganized Disorganized

Res

po

nse

Tim

e in

ms.

(dif

fere

nce

sco

res:

em

oti

on

al c

on

dit

ion

s -

neu

tral

)

Neg LowNeg HighPos LowPos High

Fig. 1. Emotional Stroop conditions by group.

L.K. Phillips et al. / Schizophrenia Research 77 (2005) 141–149146

levels of disorganization, valence�disorganization (F

[1, 23]=8.38, p=.01, eta= .52), though, overall, all

participants took longer to respond to negative valence,

valence (F [1, 23]=5.90, p=.02, eta= .45). The two

groups responded significantly different to high and low

arousal, arousal�disorganization (F [1, 23]=4.38,

p=.048, eta= .40). More specifically, pairwise compar-

isons revealed a significant difference between the two

groups on the negative high arousal block of the Stroop

( p b .01, eta= .57). The analyses pertaining to the

accuracy data, though nonsignificant between those

were more disorganized and those who were less

disorganized, were in the same direction as the response

time data. The disorganized group showed a trend

toward a greater number of errors in the negatively

valenced conditions and fewer errors in the positive

conditions, F [1, 23]= .58, p=.45. In addition, the

disorganized group showed the greatest number of errors

in the negative, high arousal condition, relative to the

other emotional Stroop conditions (mean negative, high

arousal = 1.00 [SD= 1.15]; mean negative, low

arousal = .89 [SD = 1.27]; mean positive, high

arousal= .40 [SD=.52]; mean positive, low arousal= .60

[SD=1.08]).

Further support for differences in responsivity

between the two groups to emotional conditions comes

from the rate of discrimination of those who scored

higher on disorganization from those who were less

disorganized by the four conditions of the emotional

Stroop. The binary logistic regression analysis revealed

that the emotional Stroop conditions correctly pre-

dicted 90% of the group higher in disorganization and

93.3% of those lower in disorganization. Overall,

correct classification was 92% (x2 [4, N =25]=24.42,

p b .0001). A Hosmer–Lemeshow statistic (Tabachnick

and Fidell, 2001, p. 539) was employed to ensure the

use of a good model (x2 [6, N =25]= .39, p =.99).

4. Discussion

The purpose of the current study was to clarify the

disorganization symptom dimension of schizophrenia,

through an examination of emotional information

processing. Further, we aimed to disentangle respon-

sivity to valence from that of arousal, to determine

which components of emotion—valence, arousal, or

both—are differentially processed in those with higher

levels of disorganization. To do this, we employed an

objective, quantifiable measure of emotional process-

ing: the emotional Stroop. This measure allowed us to

examine response time and accuracy associated with

words differing in positive, negative, high arousal,

and low arousal emotional content.

L.K. Phillips et al. / Schizophrenia Research 77 (2005) 141–149 147

Individuals diagnosed with schizophrenia or

schizoaffective disorder, as a whole, did not respond

differently from the control group in response time or

accuracy to words with valenced and arousing

content. Once the individuals diagnosed with schiz-

ophrenia or schizoaffective disorder were separated

according to level of disorganization symptomatol-

ogy, group differences within the schizophrenia/

schizoaffective group emerged. Specifically, the

disorganized group displayed increased response

time to negative and decreased response time to

positive content. In addition, the disorganized group

responded with increased response times particularly

to the negative high arousal condition, relative to the

neutral condition. Similarly, though not significant,

individuals who were disorganized showed the

highest number of errors in the negative conditions

and the fewest in the positive conditions. Further, the

high rate of accuracy in discrimination of disorgani-

zation by the emotional Stroops suggests that there

may be an overlap in the mechanisms associated

with disorganization with those that contribute to

aberrant emotional processing, particularly to that of

negative affective content. Similar to that mentioned

in the above analyses, it was the words with negative

content with higher arousal ratings that most

distinguished those individuals who were more

disorganized from those who were less.

Emotion and cognition are highly integrated

processes. Together, they contribute to the monitoring

and control of thought and behavior (Gray, 2004).

Differences in the processing of negative, more highly

arousing stimuli, by individuals who are more

disorganized, may be associated with the disinhibition

of cognitive control that is found in this population.

The impact of arousal levels on cognition is evi-

denced by the disruptive influence increased arousal

can have on certain cognitive function, such as

selective attention (Burbridge and Barch, 2002).

Indeed, thought disorder and disorganization in

schizophrenia have been associated with diminished

inhibitory function, coupled with heightened arousal

and increased emotional intensity. In addition, rather

than increasing attention to task relevant information,

abnormal emotional processing may interfere and

result in the loss of perspective that has been observed

in individuals who are disorganized (Harrow et al.,

1989).

Aberrant emotional processing, evident in this

disorganized sample, may be associated with an

increased sensitivity to emotional stress. Indeed,

cortisol change, indexing novelty or stress, has been

associated with disorganization symptom severity

(Walder et al., 2000). Further, since stress sensitivity

has been a predecessor of psychotic episodes, under-

standing which symptoms accompany abnormalities

in emotional processing might be useful in under-

standing the mechanisms involved in the exacerba-

tion of symptomatology. Such information has the

potential to lead to improved treatment and preven-

tion strategies.

There were significant differences between the

schizophrenia/schizoaffective group and the healthy

control group on demographic variables, such as

education, WTAR, and medication status. However,

given there were no significant differences among

the three groups on emotional Stroop performance,

and given other confounds raised by matching on

such variables (Meehl, 1970), we believe that the

demographic differences do not pose significant

challenge to our conclusions. Further, because there

were no significant differences between those higher

in Disorganization and those lower on any of the

demographic variables (gender, age, education,

WTAR, handedness, age of onset, length of illness,

medication status, and diagnosis) differential per-

formance on the Stroop is probably unrelated to

demographic differences.

One limitation of this study is the multiple inter-

pretations associated with performance on the Stroop

test. We are unable to determine whether increased

response time indicates increased attention toward a

stimulus or difficulty disengaging from a stimulus.

While it is especially compelling that stimuli in the

form of words, considered less ecologically valid than

faces, pictures, or film clips, elicited differential

responses among the groups, follow up work with

other forms of emotional stimuli would be helpful to

understanding the relationship between emotional

responsivity and symptoms of disorganization. Addi-

tional work aimed at examining aberrant processing in

those who are disorganized might include independent

measures of different aspects of emotional responsivity

and affective arousal, such as skin conductance and

facial electromyography (EMG). Lastly, it would be

interesting to examine emotional processing in the

Neutral

Impartial

Placid

Passable

L.K. Phillips et al. / Schizophrenia Research 77 (2005) 141–149148

relatives of individuals who are disorganized in order to

determine whether aberrant emotional processing and/

or levels of disorganization are heritable components of

the disease process.

Medium

Customary

Everyday

Neutral

Temperate

Indifferent

Centered

Tolerable

Pacifist

Passive

Acknowledgements

This work was supported by Harvard University

Restricted Funds. The authors would like to thank

Richard J. McNally for his help with revising initial

drafts of this paper.

Moderate

Constant

Appendix A. Words selected from affective norms

for English word list

Negative, low arousal Positive, low arousal

Pessimistic Reliable

Dreary Dependable

Alienated Kind

Inadequate Understanding

Weak Loved

Unwanted Considerate

Glum Carefree

Dishonest Pleasant

Hopeless Secure

Somber Sincere

Sluggish Peaceful

Gloomy Harmonious

Unremarkable Valued

Desolate Generous

Plain Sociable

Negative, high arousal Positive, high arousal

Furious Sparkling

Devastated Cheerful

Tormented Animated

Annoyed Optimistic

Reckless Passionate

Frightened Delighted

Irritable Spirited

Ruthless Witty

Desperate Excited

Wicked Splendid

Jealous Jovial

Tense Ambitious

Horrified Euphoric

Greedy Creative

Suffering Exuberant

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