Schizophrenia Research, 5 Elsevier
SCHIZO
(1991)123- I34
123
00 175
Cognitive functioning and positive and negative symptoms in schizophrenia Jean Addington,
D. Addington
and E. Maticka-Tyndale
Department of Psychiarry, Universiiy of Calgary, Calgary. Canada (Received
27 August
1990, revised received
7 November
1990, accepted
3 January
1991)
The present study examined schizophrenics’ performance on a variety of cognitive measures in order to explore the relationship between schizophrenic symptoms and cognitive performance. The Wechsler Adult Intelligence Scale and a battery of neuropsychological tests, developed at the Montreal Neurological Institute, were administered to 38 acutely ill, hospitalized schizophrenics. Patients were diagnosed using DSM III criteria. Negative symptoms were assessed with the SANS and positive symptoms with the SAPS. Both the cognitive tests and the symptom rating scales were re-administered to this sample at a 6 month follow-up period. Analyses revealed that, at both time periods cognitive deficits were more likely to be associated with high negative symptom ratings than with positive symptoms. Only certain tests showed significant improvement at the follow-up period. Furthermore, improved cognitive functioning was related to an improvement in positive, but not negative, symptoms. Key words: Cognitive
function;
Positive
symptom;
Negative
symptom:
INTRODUCTION
Approaches to subtyping schizophrenia have made use of the concepts of positive and negative symptoms (Crow, 1980a,b; Andreasen, 1982). Recent studies have begun to examine, more extensively, the relationship between cognitive functioning and positive and negative symptoms in schizophrenia. This issue has been addressed (Bilder et al., 1985; Cornblatt et al., 1985; Green and Walker, 1985, 1986a,b) using different measures of information processing and neuropsychological assessment. Results of these studies have shown that, using a wide variety of tests, positive and negative symptoms are associated with different patterns of performance deficits on cognitive tests, and not that negative symptoms are uniquely associated with Correspondence to: J. Addington, Department Holy Cross Hospital, 2210 2nd Street, Calgary, T2S 1S6, Canada.
0920-9964/91/$03.50
c> 1991 Elsevier
of Psychology, S.W., Alberta
Science Publishers
B.V.
(Schizophrenia)
general cognitive impairment. More specifically, positive symptoms have been found to be associated with deficits on verbal tests and with deficits in selective attention (Cornblatt et al., 1985; Green and Walker, 1985, 1986b). This is in contrast to negative symptoms which appear to be associated more with deficits on various tests of visual-spatial ability (Kolakowska et al., 1985; Green and Walker, 1986a). Negative symptoms have also been associated with poor performance on measures of backward masking (Green and Walker, 1986a; Braff, 1989). However, no definite pattern of impairment has been established. Extensive neuropsychological testing in schizophrenics has been conducted in attempts to link schizophrenia to a left hemisphere dysfunction (Flor-Henry, 1969; Flor-Henry and Yeudall, 1979). However, these studies have not been replicated. Other research (Kolb and Wishaw, 1983) has shown that, compared to normals, schizophrenics performed more poorly on tests of right temporal lobe and right and left frontal lobe functioning.
124
Additionally, there is a growing body of evidence demonstrating a convergence of findings suggesting the possibility of a frontal system dysfunction in patients suffering from schizophrenia (Andreasen et al., 1986; Morihisa and Weinberger, 1986; Gruzelier et al., 1988). For example, data using positron emission tomographic scanning have provided some partial confirmation for the hypofrontality hypothesis. although findings are by no means consistent. Brain electrical activity mapping has also documented decreased frontal lobe activity in schizophrenics and an association with frontal lobe atrophy. Weinberger et al. (1986) observed an inability in schizophrenics to activate the dorsolateral region of the frontal system when they were doing the Wisconsin Card Sort test. Unfortunately, most of the research examining cognitive functioning in schizophrenics is crosssectional and longitudinal studies are rare. In a sample of ten schizophrenics, Asarnow and MacCrimmon (1982) showed that the schizophrenics performed more poorly than controls on the forced choice span of apprehension test at both I and 12 weeks after hospitalization, despite an improvement in symptoms. Nuechterlein and his associates (Nuechterlein et al., 1986) showed, in a sample of 40 schizophrenics, that deficits on measures of sustained attention were consistently associated with negative symptoms of schizophrenia across both the inpatient and outpatient assessments. These results suggest that the relationship is not limited to a cross-sectional association within episodes. This present study was designed to examine the relationship between cognitive functioning and positive and negative symptoms of schizophrenia. first at a period of hospitalization and again at a 6 month follow-up period of relative remission; and secondly, to examine whether improvement in cognitive functioning is associated with any improvement in symptoms. Based on current research. it was hypothesized that positive and negative symptoms would be differentially related to performance on a variety of cognitive tests. More specifically, it was predicted that negative but not positive symptoms would be related to deficits on tests that are considered to measure frontal lobe functioning.
METHODOLOGY SLd7jrct.s The sample consisted of 38 inpatient schizophrenics (25 males and 13 females) who were consecutive voluntary admissions to a psychiatric unit in a general hospital. Subjects were required to have a diagnosis of schizophrenia according to DSM III criteria. Subjects were excluded if they had any of the following: (1) evidence of an organic central nervous system disorder; (2) significant and habitual drug or alcohol abuse in the past year; (3) mental retardation; or (4) physical disabilities which made writing and drawing impossible. Exclusion criteria were determined by chart review, from clinical interview and from the medical assessment of the subjects on admission. The power of a sample of 38 to identify medium (0.3) to strong (0.5) correlations as significant at the 0.05 level, is 0.58 and 0.95 respectively (Cohen, 1969). This sample had an average age of 30.9 years (range= 17754 years, SD = 8.73). and an average of 11.5 years of education. The average number of admissions of this sample was 5.26 (range I ~ 16, SD = 3.70) and the average age of first admission to hospital was 22.4 years (range 13-39 years, SD = 5.44). Test instruments (1) Diagnosis Patients were diagnosed with DSM III criteria for schizophrenia based on the expanded version of the Present State Examination (PSE). The PSE was developed by Wing et al. (1974) and has been modified at the National Institute of Mental Health Clinical Research Center at the University of California at Los Angeles. It is a structured interview consisting of 145 items (Wing et al., 1974). (2) SJ~mpt0m.r (aJ The Scale jar the A~ssessment qf Negative Symptoms (SANSj. SANS was developed by Andreasen (1981). This scale contains items for rating 25 negative symptoms. including five global symptoms (alogia, affective flattening, avolitionand attentional anhedonia-asociality, apathy,
125
impairment). Each of the five global measures is broken down into observable behavioral components that are rated on a six-point scale. Each symptom in the scale was rated from severe (5) to absent (0). The symptom ratings were summed to provide a global score for negative symptoms. (h) The Scule For the Assessment of’ Positiw Symptoms (SAPS). SAPS was developed by Andreasen (I 984). This scale contains items for rating 32 positive symptoms. including four global symptoms (bizarre behavior, hallucinations, delusions, and formal thought disorder). Each of the four global measures is broken down into observable behavioral components that are rated on a sixpoint scale. Each symptom in the scale was rated from severe (5) to absent (0). Earlier research with this sample demonstrated that when symptoms were assessed first at hospitalization then at a 6 month follow-up period, positive and negative symptoms were not inversely related. In comparison to positive symptoms negative symptoms were highly intercorrelated at both phases of the illness; whereas positive symptoms were not (Addington and Addington. 1991). Based on these findings, which have been supported elsewhere in the literature. the five negative symptoms were entered into this analysis as a single negative syndrome and the four positive symptoms were entered separately.
(3) Cognitive ,finctioning (uJ The Wechsler Adult Intelligence Scale (WAIS). All subtests of the WAIS were used. (h) The Wechsler Memory Scale. Both immediate and delayed recall were measured for both the verbal and non-verbal material. Subjects were given a delayed recall test of the WMS logical stories, paired associates and visual reproduction, approximately 30 minutes after the initial recall test (Mimer, 1975; Taylor, 1979). ic) The Rey-Osterrieth Complex Figure (Rey, 1942; Osterrieth, 1944). The subject is instructed to copy the figure as exactly as he or she can. Time for completion is recorded and both the test figure and subject’s drawings are removed. A delayed recall trial is given after 45 min. when the subject is asked to reproduce as much of the figure as he/she can remember. This is considered a test
of the non-verbal memory function of the right temporal lobe. (Lz) The Ne,vcomhe Word Fluency (Newcombe, 1969). This test was designed to assess verbal fluency in brain damaged subjects. Subjects are asked to name as many different items as possible from given categories in a 60 s period. The categories are (i) objects, (ii) animals, (iii) alternately birds and colors. (e) Chicago Word Fluency (Thurstone & Thurstone, 1943). Subjects are allowed 5 min in which to write down as many words as possible beginning with the letter S. After this they are allowed a further 4 min for the harder task of writing down four letter words beginning with C. Impaired verbal fluency has been associated with frontal lobe damage (Milner, 1975). (‘f) Jones-Gotmun Design Fluenq~ Test (JonesGotman & Milner, 1977). This test is intended to be a non-verbal analogue of the word fluency test. The test has two parts: a free condition lasting 5 min and a fixed condition lasting 4 min. Subjects are asked to draw as many, different, unnameable figures as they can. Creations are restricted to those that neither represent actual objects nor were derived from such objects. Scribbles are also against the rules. The second part of the test is presented as being similar to the first, except that this time each drawing has to consist of exactly four lines. Definitions of a line are explained: straight line, circle, and curve. This test has been found to be sensitive to anterior lesions of the non-dominant hemisphere in particular to frontal lobe function and often to temporal lobe functioning (Jones-Gotman and Milner, 1977). (g) The Wisconsin Curd Sorting Test ( WCST). In this test the subject is presented with four stimulus cards, bearing different designs that differ in form, color or number. The subject’s task is to sort a pack of cards that vary along these dimensions. The correct sorting strategy is changed. without warning to the subject, every time he sorts 10 consecutive cards correctly. Testing is completed when the subject successfully completes six categories or sorts 128 cards, whichever comes first. Scores were calculated for number of categories achieved, number of errors, and number of perseverative responses. This test is considered to be sensitive to lesions in the frontal lobe (Mimer, 1975).
126
Procedures
Subjects were assessed privately. Assessments began as soon as patients were stabilized enough to give informed consent to participate in this study and to understand task instructions (337 days after admission). The clinical diagnosis, the SANS, and the SAPS were administered by one of the authors (D.A.) who had established his interrater reliability of these measures on another sample at the UCLA Clinical Research Centre for Schizophrenia (r = 0.85). All other psychological assessments were carried out by the other author (J.A.) The psychological tests were administered in two sessions on two consecutive days, following the symptom assessment, by J.A. who was blind to the positive/negative symptomatic status of the patients, as determined by the SANS and the SAPS. The SANS and the SAPS were administered on day 1; the WAIS on day 2; and the other cognitive tests were given on day 3, in the same order as they are described above. Assessment of symptoms and cognitive functioning were repeated for each subject 6 months after the initial assessment. At follow up symptoms were assessed on day one and cognitive functioning on day 2.
RESULTS
Age of the subjects, number of admissions, and age at onset of illness were unrelated to performance on cognitive tests at either time period. Male subjects showed more perseverative responses on the WCST at time 2 (r = 0.32, p < 0.05). There were significant relationships between years of education and some of the cognitive tests. These signfiicant relationships are shown in Table 1. All subjects were taking antipsychotic medication at the time of the first assessment. At the follow-up assessment all except two patients were on maintenance dosages of medication. The cognitive profile of these two patients did not differ significantly from the mean cognitive scores of the other subjects. Chlorpromazine equivalents were calculated. Medication dose and symptoms have been shown to be unrelated in this sample (Add-
TABLE
1
Sign$cant relationships between cognitive tests and education Pearson Product Moment Correlations Educution
Cognitive test Time I
0.48** 0.36*
IQ PtQ VtQ Rey COPY Delayed verbal WCST error
0.50** memory
o.so** 0.36* 0.33*
Time 2
IQ PtQ ROY COPY Immediate visual memory
0.45** 0.40* 0.40* 0.33*
*p10.05. **pio.o1
ington and Addington, 1991). Correlational analysis showed that higher medication dose (chlorpromazine equivalent) was significantly related to lower IQ (r = - 0.34, p< 0.05) but not to any of the other cognitive tests. Pearson product moment correlations were calculated to examine the relationship between cognitive tests and symptoms at both time periods. Since previous research (Addington and Addington, 1991) has shown that at both time periods negative symptoms are highly intercorrelated, whereas positive symptoms appear to be separate measures, the summary score for negative symptoms and the individual positive symptom scores were used in this analysis. Results indicate that at both time periods poor performance on IQ, the Newcombe, and the number of errors on the WCST was signficantly related to high ratings of negative symptoms. At time 1 a high rating on delusions was significantly related to a high IQ score and few errors on the WCST; VIQ was related to high ratings of negative symptoms; and PIQ was related to high ratings of bizarre behavior. At time 2 a high rating on delusions and hallucinations in addition to negative symptoms was significantly related to poor performance on the Newcome. Low VIQ was also related to high ratings of negative symptoms. These results are presented in Table 2. In order to reduce the data the following two
127 TABLE
2
Relationship between cognitive tests and symptoms-Pearson Cognifive iests
Product Moment Correlations
Hallucinations
Delusions
Bizarre behaviour
Thought disorder
Negative q’mptoms
-0.22 -0.16 -0.21 - 0.03 0.14 - 0.25 - 0.20 -0.11 0.25 0.12 -0.05 -0.25 - 0.28 -0.10 - 0.27
0.39* 0.31 0.24 - 0.08 0.30 0.09 0.10 0.17 -0.18 - 0.32* 0.15 0.08 0.22 0.28 0.12
- 0.06 - 0.08 -0.35* 0.07 - 0.04 - 0.05 - 0.04 -0.12 - 0.04 -0.01 0.08 - 0.07 -0.16 -0.15 - 0.02
0.08 - 0.04 - 0.09 0.16 - 0.27 -0.15 -0.01 - 0.07 0.01 0.11 - 0.07 0.13 0.01 -0.15 0.21
- 0.32* -0.33* -0.19 - 0.34* 0.14 -0.11 0.04 -0.25 0.17 0.48** - 0.07 -0.18 -0.21 -0.19 -0.10
-0.12 -0.18 -0.13 - 0.40** -0.23 -0.12 -0.14 - 0.03 - 0.06 0.07 -0.14 0.19 0.04 0.10 -0.17
-0.18 - 0.20 -0.11 -0.36* - 0.09 - 0.06 - 0.09 -0.14 -0.08 0.12 ~ 0.06 - 0.23 - 0.08 -0.17 -0.10
-0.17 -0.18 -0.13 - 0.07 - 0.03 - 0.07 -0.21 - 0.28 - 0.06 0.30 0.37* - 0.22 - 0.24 - 0.07 - 0.27
- 0.01 - 0.08 - 0.22 -0.10 -0.18 -0.14 -0.16 -0.21 - 0.06 0.17 -0.15 -0.13 - 0.03 -0.13 -0.21
- 0.32* -0.21 -0.35* - 0.45** - 0.23 -0.18 -0.14 -0.19 0.24 0.31* - 0.23 -0.11 -0.13 - 0.08 -0.19
Time I
IQ VIQ PIQ Newcombe Jones-Gotman Rey COPY Rey Recall WCST categ. WCST persev. WCST error Chicago lmm. Ver. Mem Imm. Vis. Mem. Del. Ver. Mem. Del. Vis. Mem. Time 2
IQ VIQ PIQ Newcombe Jones-Gotman Rey COPY Rey Recall WCST categ. WCST persev. WCST error Chicago Imm. Ver. Mem Imm. Vis. Mem. Del. Ver. Mem. Del. Vis. Mem. *p
SCHIZO
(1991)123- I34
123
00 175
Cognitive functioning and positive and negative symptoms in schizophrenia Jean Addington,
D. Addington
and E. Maticka-Tyndale
Department of Psychiarry, Universiiy of Calgary, Calgary. Canada (Received
27 August
1990, revised received
7 November
1990, accepted
3 January
1991)
The present study examined schizophrenics’ performance on a variety of cognitive measures in order to explore the relationship between schizophrenic symptoms and cognitive performance. The Wechsler Adult Intelligence Scale and a battery of neuropsychological tests, developed at the Montreal Neurological Institute, were administered to 38 acutely ill, hospitalized schizophrenics. Patients were diagnosed using DSM III criteria. Negative symptoms were assessed with the SANS and positive symptoms with the SAPS. Both the cognitive tests and the symptom rating scales were re-administered to this sample at a 6 month follow-up period. Analyses revealed that, at both time periods cognitive deficits were more likely to be associated with high negative symptom ratings than with positive symptoms. Only certain tests showed significant improvement at the follow-up period. Furthermore, improved cognitive functioning was related to an improvement in positive, but not negative, symptoms. Key words: Cognitive
function;
Positive
symptom;
Negative
symptom:
INTRODUCTION
Approaches to subtyping schizophrenia have made use of the concepts of positive and negative symptoms (Crow, 1980a,b; Andreasen, 1982). Recent studies have begun to examine, more extensively, the relationship between cognitive functioning and positive and negative symptoms in schizophrenia. This issue has been addressed (Bilder et al., 1985; Cornblatt et al., 1985; Green and Walker, 1985, 1986a,b) using different measures of information processing and neuropsychological assessment. Results of these studies have shown that, using a wide variety of tests, positive and negative symptoms are associated with different patterns of performance deficits on cognitive tests, and not that negative symptoms are uniquely associated with Correspondence to: J. Addington, Department Holy Cross Hospital, 2210 2nd Street, Calgary, T2S 1S6, Canada.
0920-9964/91/$03.50
c> 1991 Elsevier
of Psychology, S.W., Alberta
Science Publishers
B.V.
(Schizophrenia)
general cognitive impairment. More specifically, positive symptoms have been found to be associated with deficits on verbal tests and with deficits in selective attention (Cornblatt et al., 1985; Green and Walker, 1985, 1986b). This is in contrast to negative symptoms which appear to be associated more with deficits on various tests of visual-spatial ability (Kolakowska et al., 1985; Green and Walker, 1986a). Negative symptoms have also been associated with poor performance on measures of backward masking (Green and Walker, 1986a; Braff, 1989). However, no definite pattern of impairment has been established. Extensive neuropsychological testing in schizophrenics has been conducted in attempts to link schizophrenia to a left hemisphere dysfunction (Flor-Henry, 1969; Flor-Henry and Yeudall, 1979). However, these studies have not been replicated. Other research (Kolb and Wishaw, 1983) has shown that, compared to normals, schizophrenics performed more poorly on tests of right temporal lobe and right and left frontal lobe functioning.
124
Additionally, there is a growing body of evidence demonstrating a convergence of findings suggesting the possibility of a frontal system dysfunction in patients suffering from schizophrenia (Andreasen et al., 1986; Morihisa and Weinberger, 1986; Gruzelier et al., 1988). For example, data using positron emission tomographic scanning have provided some partial confirmation for the hypofrontality hypothesis. although findings are by no means consistent. Brain electrical activity mapping has also documented decreased frontal lobe activity in schizophrenics and an association with frontal lobe atrophy. Weinberger et al. (1986) observed an inability in schizophrenics to activate the dorsolateral region of the frontal system when they were doing the Wisconsin Card Sort test. Unfortunately, most of the research examining cognitive functioning in schizophrenics is crosssectional and longitudinal studies are rare. In a sample of ten schizophrenics, Asarnow and MacCrimmon (1982) showed that the schizophrenics performed more poorly than controls on the forced choice span of apprehension test at both I and 12 weeks after hospitalization, despite an improvement in symptoms. Nuechterlein and his associates (Nuechterlein et al., 1986) showed, in a sample of 40 schizophrenics, that deficits on measures of sustained attention were consistently associated with negative symptoms of schizophrenia across both the inpatient and outpatient assessments. These results suggest that the relationship is not limited to a cross-sectional association within episodes. This present study was designed to examine the relationship between cognitive functioning and positive and negative symptoms of schizophrenia. first at a period of hospitalization and again at a 6 month follow-up period of relative remission; and secondly, to examine whether improvement in cognitive functioning is associated with any improvement in symptoms. Based on current research. it was hypothesized that positive and negative symptoms would be differentially related to performance on a variety of cognitive tests. More specifically, it was predicted that negative but not positive symptoms would be related to deficits on tests that are considered to measure frontal lobe functioning.
METHODOLOGY SLd7jrct.s The sample consisted of 38 inpatient schizophrenics (25 males and 13 females) who were consecutive voluntary admissions to a psychiatric unit in a general hospital. Subjects were required to have a diagnosis of schizophrenia according to DSM III criteria. Subjects were excluded if they had any of the following: (1) evidence of an organic central nervous system disorder; (2) significant and habitual drug or alcohol abuse in the past year; (3) mental retardation; or (4) physical disabilities which made writing and drawing impossible. Exclusion criteria were determined by chart review, from clinical interview and from the medical assessment of the subjects on admission. The power of a sample of 38 to identify medium (0.3) to strong (0.5) correlations as significant at the 0.05 level, is 0.58 and 0.95 respectively (Cohen, 1969). This sample had an average age of 30.9 years (range= 17754 years, SD = 8.73). and an average of 11.5 years of education. The average number of admissions of this sample was 5.26 (range I ~ 16, SD = 3.70) and the average age of first admission to hospital was 22.4 years (range 13-39 years, SD = 5.44). Test instruments (1) Diagnosis Patients were diagnosed with DSM III criteria for schizophrenia based on the expanded version of the Present State Examination (PSE). The PSE was developed by Wing et al. (1974) and has been modified at the National Institute of Mental Health Clinical Research Center at the University of California at Los Angeles. It is a structured interview consisting of 145 items (Wing et al., 1974). (2) SJ~mpt0m.r (aJ The Scale jar the A~ssessment qf Negative Symptoms (SANSj. SANS was developed by Andreasen (1981). This scale contains items for rating 25 negative symptoms. including five global symptoms (alogia, affective flattening, avolitionand attentional anhedonia-asociality, apathy,
125
impairment). Each of the five global measures is broken down into observable behavioral components that are rated on a six-point scale. Each symptom in the scale was rated from severe (5) to absent (0). The symptom ratings were summed to provide a global score for negative symptoms. (h) The Scule For the Assessment of’ Positiw Symptoms (SAPS). SAPS was developed by Andreasen (I 984). This scale contains items for rating 32 positive symptoms. including four global symptoms (bizarre behavior, hallucinations, delusions, and formal thought disorder). Each of the four global measures is broken down into observable behavioral components that are rated on a sixpoint scale. Each symptom in the scale was rated from severe (5) to absent (0). Earlier research with this sample demonstrated that when symptoms were assessed first at hospitalization then at a 6 month follow-up period, positive and negative symptoms were not inversely related. In comparison to positive symptoms negative symptoms were highly intercorrelated at both phases of the illness; whereas positive symptoms were not (Addington and Addington. 1991). Based on these findings, which have been supported elsewhere in the literature. the five negative symptoms were entered into this analysis as a single negative syndrome and the four positive symptoms were entered separately.
(3) Cognitive ,finctioning (uJ The Wechsler Adult Intelligence Scale (WAIS). All subtests of the WAIS were used. (h) The Wechsler Memory Scale. Both immediate and delayed recall were measured for both the verbal and non-verbal material. Subjects were given a delayed recall test of the WMS logical stories, paired associates and visual reproduction, approximately 30 minutes after the initial recall test (Mimer, 1975; Taylor, 1979). ic) The Rey-Osterrieth Complex Figure (Rey, 1942; Osterrieth, 1944). The subject is instructed to copy the figure as exactly as he or she can. Time for completion is recorded and both the test figure and subject’s drawings are removed. A delayed recall trial is given after 45 min. when the subject is asked to reproduce as much of the figure as he/she can remember. This is considered a test
of the non-verbal memory function of the right temporal lobe. (Lz) The Ne,vcomhe Word Fluency (Newcombe, 1969). This test was designed to assess verbal fluency in brain damaged subjects. Subjects are asked to name as many different items as possible from given categories in a 60 s period. The categories are (i) objects, (ii) animals, (iii) alternately birds and colors. (e) Chicago Word Fluency (Thurstone & Thurstone, 1943). Subjects are allowed 5 min in which to write down as many words as possible beginning with the letter S. After this they are allowed a further 4 min for the harder task of writing down four letter words beginning with C. Impaired verbal fluency has been associated with frontal lobe damage (Milner, 1975). (‘f) Jones-Gotmun Design Fluenq~ Test (JonesGotman & Milner, 1977). This test is intended to be a non-verbal analogue of the word fluency test. The test has two parts: a free condition lasting 5 min and a fixed condition lasting 4 min. Subjects are asked to draw as many, different, unnameable figures as they can. Creations are restricted to those that neither represent actual objects nor were derived from such objects. Scribbles are also against the rules. The second part of the test is presented as being similar to the first, except that this time each drawing has to consist of exactly four lines. Definitions of a line are explained: straight line, circle, and curve. This test has been found to be sensitive to anterior lesions of the non-dominant hemisphere in particular to frontal lobe function and often to temporal lobe functioning (Jones-Gotman and Milner, 1977). (g) The Wisconsin Curd Sorting Test ( WCST). In this test the subject is presented with four stimulus cards, bearing different designs that differ in form, color or number. The subject’s task is to sort a pack of cards that vary along these dimensions. The correct sorting strategy is changed. without warning to the subject, every time he sorts 10 consecutive cards correctly. Testing is completed when the subject successfully completes six categories or sorts 128 cards, whichever comes first. Scores were calculated for number of categories achieved, number of errors, and number of perseverative responses. This test is considered to be sensitive to lesions in the frontal lobe (Mimer, 1975).
126
Procedures
Subjects were assessed privately. Assessments began as soon as patients were stabilized enough to give informed consent to participate in this study and to understand task instructions (337 days after admission). The clinical diagnosis, the SANS, and the SAPS were administered by one of the authors (D.A.) who had established his interrater reliability of these measures on another sample at the UCLA Clinical Research Centre for Schizophrenia (r = 0.85). All other psychological assessments were carried out by the other author (J.A.) The psychological tests were administered in two sessions on two consecutive days, following the symptom assessment, by J.A. who was blind to the positive/negative symptomatic status of the patients, as determined by the SANS and the SAPS. The SANS and the SAPS were administered on day 1; the WAIS on day 2; and the other cognitive tests were given on day 3, in the same order as they are described above. Assessment of symptoms and cognitive functioning were repeated for each subject 6 months after the initial assessment. At follow up symptoms were assessed on day one and cognitive functioning on day 2.
RESULTS
Age of the subjects, number of admissions, and age at onset of illness were unrelated to performance on cognitive tests at either time period. Male subjects showed more perseverative responses on the WCST at time 2 (r = 0.32, p < 0.05). There were significant relationships between years of education and some of the cognitive tests. These signfiicant relationships are shown in Table 1. All subjects were taking antipsychotic medication at the time of the first assessment. At the follow-up assessment all except two patients were on maintenance dosages of medication. The cognitive profile of these two patients did not differ significantly from the mean cognitive scores of the other subjects. Chlorpromazine equivalents were calculated. Medication dose and symptoms have been shown to be unrelated in this sample (Add-
TABLE
1
Sign$cant relationships between cognitive tests and education Pearson Product Moment Correlations Educution
Cognitive test Time I
0.48** 0.36*
IQ PtQ VtQ Rey COPY Delayed verbal WCST error
0.50** memory
o.so** 0.36* 0.33*
Time 2
IQ PtQ ROY COPY Immediate visual memory
0.45** 0.40* 0.40* 0.33*
*p10.05. **pio.o1
ington and Addington, 1991). Correlational analysis showed that higher medication dose (chlorpromazine equivalent) was significantly related to lower IQ (r = - 0.34, p< 0.05) but not to any of the other cognitive tests. Pearson product moment correlations were calculated to examine the relationship between cognitive tests and symptoms at both time periods. Since previous research (Addington and Addington, 1991) has shown that at both time periods negative symptoms are highly intercorrelated, whereas positive symptoms appear to be separate measures, the summary score for negative symptoms and the individual positive symptom scores were used in this analysis. Results indicate that at both time periods poor performance on IQ, the Newcombe, and the number of errors on the WCST was signficantly related to high ratings of negative symptoms. At time 1 a high rating on delusions was significantly related to a high IQ score and few errors on the WCST; VIQ was related to high ratings of negative symptoms; and PIQ was related to high ratings of bizarre behavior. At time 2 a high rating on delusions and hallucinations in addition to negative symptoms was significantly related to poor performance on the Newcome. Low VIQ was also related to high ratings of negative symptoms. These results are presented in Table 2. In order to reduce the data the following two
127 TABLE
2
Relationship between cognitive tests and symptoms-Pearson Cognifive iests
Product Moment Correlations
Hallucinations
Delusions
Bizarre behaviour
Thought disorder
Negative q’mptoms
-0.22 -0.16 -0.21 - 0.03 0.14 - 0.25 - 0.20 -0.11 0.25 0.12 -0.05 -0.25 - 0.28 -0.10 - 0.27
0.39* 0.31 0.24 - 0.08 0.30 0.09 0.10 0.17 -0.18 - 0.32* 0.15 0.08 0.22 0.28 0.12
- 0.06 - 0.08 -0.35* 0.07 - 0.04 - 0.05 - 0.04 -0.12 - 0.04 -0.01 0.08 - 0.07 -0.16 -0.15 - 0.02
0.08 - 0.04 - 0.09 0.16 - 0.27 -0.15 -0.01 - 0.07 0.01 0.11 - 0.07 0.13 0.01 -0.15 0.21
- 0.32* -0.33* -0.19 - 0.34* 0.14 -0.11 0.04 -0.25 0.17 0.48** - 0.07 -0.18 -0.21 -0.19 -0.10
-0.12 -0.18 -0.13 - 0.40** -0.23 -0.12 -0.14 - 0.03 - 0.06 0.07 -0.14 0.19 0.04 0.10 -0.17
-0.18 - 0.20 -0.11 -0.36* - 0.09 - 0.06 - 0.09 -0.14 -0.08 0.12 ~ 0.06 - 0.23 - 0.08 -0.17 -0.10
-0.17 -0.18 -0.13 - 0.07 - 0.03 - 0.07 -0.21 - 0.28 - 0.06 0.30 0.37* - 0.22 - 0.24 - 0.07 - 0.27
- 0.01 - 0.08 - 0.22 -0.10 -0.18 -0.14 -0.16 -0.21 - 0.06 0.17 -0.15 -0.13 - 0.03 -0.13 -0.21
- 0.32* -0.21 -0.35* - 0.45** - 0.23 -0.18 -0.14 -0.19 0.24 0.31* - 0.23 -0.11 -0.13 - 0.08 -0.19
Time I
IQ VIQ PIQ Newcombe Jones-Gotman Rey COPY Rey Recall WCST categ. WCST persev. WCST error Chicago lmm. Ver. Mem Imm. Vis. Mem. Del. Ver. Mem. Del. Vis. Mem. Time 2
IQ VIQ PIQ Newcombe Jones-Gotman Rey COPY Rey Recall WCST categ. WCST persev. WCST error Chicago Imm. Ver. Mem Imm. Vis. Mem. Del. Ver. Mem. Del. Vis. Mem. *p
