Nordic Journal of Psychiatry
ISSN: 0803-9488 (Print) 1502-4725 (Online) Journal homepage: http://www.tandfonline.com/loi/ipsc20
Karolinska Scales of Personality, cognition and psychotic symptoms in patients with schizophrenia and healthy controls Björn Mikael Nilsson, Gunnar Holm & Lisa Ekselius To cite this article: Björn Mikael Nilsson, Gunnar Holm & Lisa Ekselius (2015): Karolinska Scales of Personality, cognition and psychotic symptoms in patients with schizophrenia and healthy controls, Nordic Journal of Psychiatry To link to this article: http://dx.doi.org/10.3109/08039488.2015.1048720
Published online: 18 Jun 2015.
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Date: 05 November 2015, At: 19:03
Karolinska Scales of Personality, cognition and psychotic symptoms in patients with schizophrenia and healthy controls BjÖrn Mikael Nilsson, Gunnar Holm, Lisa Ekselius
Nilsson BM, Karolinska Scales of Personality, cognition and psychotic symptoms in patients with schizophrenia and healthy controls. Nord J Psychiatry Early Online;68:1–9
Downloaded by [Universite Laval] at 19:03 05 November 2015
Background: Studies on both personality dimensions and cognition in schizophrenia are scarce. The objective of the present study was to examine personality traits and the relation to cognitive function and psychotic symptoms in a sample of patients with schizophrenia and healthy controls. Method: In total 23 patients with schizophrenia and 14 controls were assessed with the Karolinska Scales of Personality (KSP). A broad cognitive test programme was used, including the Wechsler Adult Intelligence Scales, the Finger-Tapping Test, the Trail Making Test, the Verbal Fluency Test, the Benton Visual Retention Test, the Wisconsin Card Sorting Test and Rey Auditory Verbal Learning Test . Results: Compared with controls, the patients exhibited prominent elevations on KSP scales measuring anxiety proneness and neuroticism (P 0.000005–0.0001), on the Detachment scale (P 0.00009) and lower value on the Socialization scale (P 0.0002). The patients also scored higher on the Inhibition of Aggression, Suspicion, Guilt and Irritability scales (P 0.002–0.03) while the remaining five scales did not differ between patients and controls. KSP anxiety-related scales correlated with the Positive and Negative Symptoms Scale (PANSS) general psychopathology subscale. Cognitive test results were uniformly lower in the patient group and correlated with PANSS negative symptoms subscale. There was no association between KSP scale scores and PANSS positive or negative symptoms. Conclusion: The patients revealed a highly discriminative KSP test profile with elevated scores in neuroticism- and psychoticism-related scales as compared to controls. Results support previous findings utilizing other personality inventories in patients with schizophrenia. Cognitive test performance correlated inversely with negative symptoms. • Cognition, Negative symptoms, Schizophrenia, Personality. Björn Mikael Nilsson, Department of Neuroscience, Psychiatry, Uppsala University, SE 751 85 Uppsala, Sweden; E-mail: [email protected]; Accepted 29 April 2015.
S
chizophrenia is a chronic disease with a highly variable lifetime course. Although successful pharmacological treatment may result in symptomatic relief from positive symptoms, the negative symptoms often remain and frequently also produce a continuous need for support to keep up basal daily activities. A relationship between severe negative symptoms and an unfavourable long-term outcome is accordingly reported in previous studies (1–3). Cognitive symptoms are also associated with a worse outcome (4). The cognitive dysfunctions in schizophrenia cover a wide span of disturbances regarding attention, working memory, information processing and executive functions (5–7). This generalized impairment also appears to be remarkably stable over time both in individuals (8) and schizophrenia © 2015 Informa Healthcare
populations (6). Cognitive impairment is thus so prominent in the clinical picture that it has been proposed to have a diagnostic value for schizophrenia (9). Furthermore, personality factors may also be related to longterm outcome in schizophrenia. Psychiatry has long searched for stable measures of personality traits that have nosological and biological relevance. Such personality traits should not be influenced by cultural or socio-economic boundaries. They should also in a predictable way wield an influence on how individuals deal with everyday challenges. From a clinical perspective, personality traits have been proposed to be of importance for the ability to cope with somatic and psychiatric diseases (10). Among the personality inventories used in psychiatric research are the Eysenck Personality DOI: 10.3109/08039488.2015.1048720
Downloaded by [Universite Laval] at 19:03 05 November 2015
B M Nilsson et al.
Questionnaire (EPQ) (11), the Temperament and Character Inventory (TCI) (12) and five-factor dimensional instruments (extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience) such as the Big Five (13) or the revised NEO Personality Inventory (NEO-PI-R) (14). Some instruments are considered to be more biologically founded and the temperament dimensions in Cloninger’s biosocial model are thus claimed to be heritable (12). The Karolinska Scales of Personality (KSP) also has its origin in biological research (15, 16). The KSP instrument was developed for the measurement of personality in relation to biological correlates with a specific purpose to recognize high-risk individuals and vulnerability factors for psychopathology. KSP was originally intended for use in both healthy individuals and in psychiatric disorders, among them schizophrenia. KSP has been used in different biological studies (17) but there are no records focusing on the KSP scales profile in patients with schizophrenia compared to controls or in relation to cognitive function. In schizophrenia, previous studies with different personality inventories have indicated the presence of stable personality traits regarding the dimensions neuroticism/harm avoidance and extraversion (18–22). In general, specific personality traits are thought to impair social functioning and the ability to cope with everyday difficulties (21). To a great extent, the ability to cope with a life-long disease, persisting symptoms and cognitive disturbances, is closely related to outcome in schizophrenia. The personality traits reported in schizophrenia, with higher levels of neuroticism and lower levels of extraversion (18, 19), have thus been associated with more avoidant and fewer problem-solving coping strategies (10). Linked to the capacity of coping is also insight, i.e. the awareness of an existing illness and the need for treatment. In schizophrenia, insight has been associated both with executive cognitive functioning and personality dimensions (23, 24). Further, the capacity for self-reflectivity and other aspects of metacognition are closely intertwined with insight and consequently proposed to be major predictors for functional outcome (25). Meta-cognition has repeatedly been associated with cognitive parameters in schizophrenia (26, 27). Another question is whether specific personality traits like schizotypy will increase the risk for schizophrenia (28). Epigenetic mechanisms may here have a regulatory function in the transformation into different phenotype outcomes regarding personality, cognition and the development of disease. Several candidate genes have thus been identified and suggested as vulnerable for epigenetic changes like DNA methylation and the risk for schizophrenia, among them the serotonin receptor TR2A gene and the brain-derived neurotrophic factor (BDNF) gene (29, 30).
2
Overall, there are a number of genetic studies using different kinds of personality assessments in schizophrenia (31, 32). Studies are fewer on personality parameters in relation to clinical psychotic symptoms (33–35) or outcome (21, 36, 37), and studies using broad neuropsychological examinations are also scarce (24). Some studies have explored a limited selection of cognitive examinations together with measurement of personality dimensions (10, 18), but to our knowledge there are no studies using the KSP, symptom assessment, and an extensive cognitive test battery in patients with schizophrenia and controls. The aim of the present study was therefore to examine personality traits, cognition and psychotic symptoms in patients with schizophrenia in comparison with a healthy control group.
Patients and methods Participants
The study was approved by the regional ethical review board in Uppsala and performed in accordance with the Declaration of Helsinki. All subjects received oral and written information about the full nature of the study before giving written consent to participate. Both newly admitted first episode patients and chronic patients aged 18–50 years, with DSM-IV diagnosed schizophrenia or schizophreniform disorders were recruited consecutively. The participants are a subset of a larger research sample recruited in Uppsala, Sweden, from which cognition in electrodermal non-responders is also reported (38). In total, 30 patients and 17 controls were recruited originally (39). From this group, seven patients and three controls were lost for follow-up with personality examinations, in most cases due to non-compliance. The present sample thus comprised 23 patients and 14 controls. Four of the patients were antipsychotic naïve and 19 patients were treated with second-generation antipsychotics. The healthy controls were recruited through a newspaper advertisement.
Procedures The personality assessments and the cognitive examinations were carried out in a stable phase of illness in the patients. All participants were assessed with the Karolinska Scales of Personality and the Positive and Negative Syndrome Scale (PANSS). A broad cognitive test battery was also administered. While all patients performed the Halstead Reitan Finger tapping test (FTT), the Trail Making Test (TMT) and Benton’s Visual Retention Test (BVRT), there were some dropouts on other tests. Two patients did not perform the Wechsler Adult Intelligence Scale (WAIS) and one patient was administered a limited subset of WAIS scales due to language difficulties. Two other patients did not fulfil the Wisconsin Card Sorting Test (WCST) or the Verbal Fluency Test. Five patients NORD J PSYCHIATRY·EARLY ONLINE·2015
Personality and cognition in schizophrenia
Downloaded by [Universite Laval] at 19:03 05 November 2015
did not participate in the Rey Auditory Verbal Learning Test (RAVLT). The controls completed all tests. All participants were examined with PANSS (40), a modified Extrapyramidal Symptom Rating Scale (ESRS) (41) and Strauss and Carpenter’s Prognostic Scale for outcome (42). ESRS scores were the sum points on ESRS subscales I–IV, consisting of a questionnaire for extrapyramidal and movement disorders plus examinations for Parkinsonism, akathisia, dystonia and dyskinesia. Items V–VIII in the original ESRS scale are Clinical Global Impression scales of the same symptoms and were omitted from this study. The SCPS items used five response steps from 0–4 and covered the original four items: hospital admissions, social contacts, work, and symptoms. Characteristics of patients and controls are exhibited in Table 1.
Personality assessment KSP consists of 15 scales with 135 items altogether. The KSP scales are Somatic Anxiety (SA), Psychic Anxiety (PA), Muscular Tension (MT), Psychasthenia (PSA), Impulsiveness (IMP), Monotony Avoidance (MA), Socialization (SO), Verbal Aggression (VA), Indirect Aggression (INDA), Irritability (IRR), Suspicion (SU), Guilt (GU), Inhibition of Aggression (INHA), Social Desirability (SD) and Detachment (DET). For a description of the personalities gaining high scores in the different KSP scales see Gustavsson et al. (43). KSP items use four response steps from “does not apply at all” to “applies completely”. The point responses were transferred to T-scores with a mean of 50 and standard deviation (SD) 10. KSP was administered as a self-report instrument. Also included in the analysis were four KSP factors used in several genetic studies (44); neuroticism (SA, PA, Table 1. Characteristics of patients and controls.
Gender: male/female Age in years Education: 12 years/ 12 years Duration of illness in years Antipsychotic medication in mg‡ PANSS total PANSS positive subscale PANSS negative subscale PANSS general subscale Strauss–Carpenter scale ESRS subscales I-IV sum
Patients n 23
Controls n 14
P-value
16/7 32.0 (8.9) 6/17 7.5 (8.1) 301.7 (174.7) 68.8 (10.5) 15.6 (4.4) 20.0 (5.8) 33.2 (4.9) 9.1 (3.2) 13.1 (10.4)
9/5 33.3 (8.4) 2/12 – – 32.6 (1.7) 7.8 (0.9) 7.4 (0.8) 17.4 (1.0) 15.7 (0.7) 1.1 (1.4)
NS* NS NS† – – ND ND ND ND ND ND
Mann Whitney U-tests, means (and standard deviation) unless otherwise noted. ESRS, Extrapyramidal Symptom Rating Scale; ND, not determined (p 0.00001); NS, not significant; PANSS, Positive and Negative Syndrome Scale. *Chi-squared test. †Fisher’s exact test. ‡Chlorpromazine equivalents. NORD J PSYCHIATRY·EARLY ONLINE·2015
MT, PSA, INHA, GU and SO), extraversion (IMP and MA), psychoticism (DET and SU) and non-conformity (SD, INDA, VA and IRR). Factor analyses of KSP scales in different populations have yielded slightly different factor solutions. The present solution goes back to the factor analysis by Gustavsson et al. (45) and has been used in several studies with minor modifications (46).
Cognitive testing Cognitive testing was performed during 2–3 sessions depending on the participants’ cognitive speed and motivation. The tests used in the study were chosen to examine relevant cognitive functions in patients newly diagnosed with schizophrenia and to cover the following cognitive domains: verbal comprehension and fluency, short-/long-term memory, perceptual organization, psychomotor function, executive function and processing speed. The revised WAIS (WAIS-R) include six verbal scales: Information, Digit Span, Vocabulary, Arithmetic, Comprehension, Similarities. Further, WAIS-R comprises five performance scales: Picture Completion, Picture Arrangement, Block Design, Object Assembly and Digit Symbol (47, 48). Some of the subtests are related to verbal comprehension (Information, Vocabulary, Similarities and Comprehension), others to short-term memory (Digit Span, Arithmetic and Digit Symbol) and perceptual organization (Picture Completion, Picture Arrangement, Block Design and Object Assembly). Based on test results, verbal (IQV), performance (IQP) and full-scale intelligence quotient (IQ) can be calculated. WAIS raw scores were transformed to age-adjusted scores by the means of Swedish normative data. The RAVLT uses a simple word-list paradigm and measures immediate memory span, learning and retention (48). The Controlled Oral Word Association Test (COWAT) is a verbal fluency test measuring the number of words associated with specific letters during a 3-min test period (48). The Halstead Reitan FTT is a psycho-motor test that measures motor speed and dexterity (48, 49). The Trail-Making Test A (TMT A) and B (TMT B) evaluate conceptual and visuomotor tracking and involve motor speed and attention as well as executive function. Time to completion is the primary measure in TMT (48, 50). The WCST assesses abstract reasoning, concept formation and flexibility. WCST has been useful in analyses of disordered executive function in various psychiatric and neurological diseases. A number of scoring alternatives are available. In schizophrenia the ability for shift-making and cognitive endurance are crucial for executive function in everyday living. The number of perseverative errors, non-perseverative errors and categories achieved are presented here (48, 51). The BVRT is a visual recall test that implies drawing of geometrical figures after 10-s exposure. Both number of correct designs and errors are scored (48).
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B M Nilsson et al.
Statistical analysis
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Scores on KSP, COWAT, FTT, TMT and WCST were transformed to age- and gender-adjusted T scores with a mean of 50 and SD of 10. The T-score transformation on “inverted” tests, like WCST errors or TMT, also results in a homogenous data interpretation; lower score represents worse performance. Mann-Whitney U-tests were used for group comparisons. P-values of 0.05 were considered to indicate a significant difference. Dichotomous variables such as gender were analysed with Chisquared tests. When the number of observations were low ( 5), Fisher’s exact test was used. Correlation analysis was performed with the Spearman rank order correlation. All statistical calculations were performed with STASTISTICA version 12.0 software.
Results
Personality KSP scores are shown in Table 2. The patients exhibited high scores in four scales (SA, PA, MT, PSA) related to factor neuroticism as well as low scores in SO also belonging to the same factor. The scale DET was also elevated in the patient group. The differences between groups on some scales, e.g. IRR, may in part be due to relatively lower scores in the control group. Taken Table 2. Karolinska Scales of Personality. Differences between patients and controls. Mann Whitney U-tests, means (and standard deviation). Patients n 23 Somatic Anxiety Psychic Anxiety Muscular Tension Psychasthenia Impulsiveness Monotony Avoidance Socialization Verbal Aggression Indirect Aggression Irritability Suspicion Guilt Inhibition of Aggression Social Desirability Detachment Factor 1. Extraversion* Factor 2. Neuroticism† Factor 3. Psychoticism‡ Factor 4. Non-conformity§
60.6 60.5 57.4 64.1 45.7 46.3 39.4 42.6 49.1 48.6 52.6 51.2 58.7 57.0 57.1 46.1 56,0 54,9 49,3
(10.4) (15.0) (10.1) (13.9) (13.0) (14.3) (12.1) (12.1) (7.7) (12.3) (10.2) (11.0) (11.1) (12.7) (12.7) (11.6) (6.3) (9.5) (5.0)
Controls n 14 40.8 40.1 42.2 40.4 50.6 52.0 56.0 45.6 47.1 38.8 42.7 43.4 47.9 56.0 40.4 51.3 44.5 41.6 46.9
(5.3) (5.9) (6.7) (8.6) (9.4) (7.5) (6.6) (8.3) (8.5) (6.1) (6.3) (5.4) (7.6) (8.1) (6.3) (7.8) (3.6) (5.9) (4.2)
P-value 0.000005 0.00004 0.0001 0.000009 NS NS 0.0002 NS NS 0.01 0.002 0.03 0.006 NS 0.00009 NS 0.0000001 0.00004 NS
NS, not significant. *Impulsiveness, Monotony Avoidance. †Somatic Anxiety, Psychic Anxiety, Muscular Tension, Psychasthenia, Inhibition of Aggression, Guilt, Socalization. ‡Detachment, Suspicion. §Indirect Aggression, Verbal Aggression, Irritability, Social Desirability.
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together, the results constitute the discriminative profile exhibited in Fig. 1 which depicts the differences in T-scores between patients and controls (mean T-score in patients minus mean T-score in controls for every KSP scale). There was no correlation between KSP scales and demographic data in the two groups. In the patients, KSP SA, MT and DET correlated with the PANSS general psychopathology subscale (r 0.57, P 0.004, r 0.58, P 0.004 and r 0.52, P 0.010 respectively). The KSP scales correlated with few cognitive parameters in the patient group; IRR with IQV (r 0.47, P 0.04), DET and SU with WCST non-perseverative errors (r 0.54, P 0.01 and r 0.44, P 0.04 respectively) and SA with Rey immediate recall (r 0.49, P 0.04). When the four-factor model (neuroticism, extraversion, psychoticism and non-conformity) was applied, pronounced divergences between patients and controls were seen in neuroticism and psychoticism factors. There were no correlations between the four factors either in the patient or in the control group. The overlapping correlations between separate scales and other factors were few in the patient group. PSA thus correlated with the nonconformity factor (r 0.63, P 0.002). Further, SA and SO correlated with the psychoticism factor (r 0.48, P 0.02 and r 0.56, P 0.005 respectively). The psychoticism factor also correlated with WCST nonperseverative errors (r 0.60, P 0.004) in the patients. There were no other correlations between any KSP scale or factor and any cognitive measure. In the control group there were significant inverse correlations between KSP subscale DDET and TMT A (r 0.67, P 0.008) as well as between DDET and COWAT (r 0.67, P 0.009).
Cognition The patients exhibited lower results than the controls on all administered tests (Table 3). Highly significant differences were seen in some of the WAIS verbal subtests, WAIS Digit Symbol Coding and TMT B. There were expected correlations between different cognitive instruments both in patients and controls. In the patients, PANSS negative symptoms exhibited the most consistent pattern of correlation with cognitive parameters (Table 3). Digit Symbol Coding, TMT B along with Rey learning tests thus showed the highest correlation, but all cognitive tests except Information, Vocabulary, Object Assembly, WCST non-perseverative errors and the psychomotor FTT tests correlated with PANSS negative symptoms (Table 3). As a rudimentary measure of the insight dimension, the PANSS item G12, Lack of Judgement and Insight, was analysed separately regarding possible association to personality or cognitive parameters in the patients. No such correlations were found. Regarding demographic NORD J PSYCHIATRY·EARLY ONLINE·2015
Personality and cognition in schizophrenia Karolinska Scales of Personality Differences between Patients and Controls SA
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ISSN: 0803-9488 (Print) 1502-4725 (Online) Journal homepage: http://www.tandfonline.com/loi/ipsc20
Karolinska Scales of Personality, cognition and psychotic symptoms in patients with schizophrenia and healthy controls Björn Mikael Nilsson, Gunnar Holm & Lisa Ekselius To cite this article: Björn Mikael Nilsson, Gunnar Holm & Lisa Ekselius (2015): Karolinska Scales of Personality, cognition and psychotic symptoms in patients with schizophrenia and healthy controls, Nordic Journal of Psychiatry To link to this article: http://dx.doi.org/10.3109/08039488.2015.1048720
Published online: 18 Jun 2015.
Submit your article to this journal
Article views: 28
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ipsc20 Download by: [Universite Laval]
Date: 05 November 2015, At: 19:03
Karolinska Scales of Personality, cognition and psychotic symptoms in patients with schizophrenia and healthy controls BjÖrn Mikael Nilsson, Gunnar Holm, Lisa Ekselius
Nilsson BM, Karolinska Scales of Personality, cognition and psychotic symptoms in patients with schizophrenia and healthy controls. Nord J Psychiatry Early Online;68:1–9
Downloaded by [Universite Laval] at 19:03 05 November 2015
Background: Studies on both personality dimensions and cognition in schizophrenia are scarce. The objective of the present study was to examine personality traits and the relation to cognitive function and psychotic symptoms in a sample of patients with schizophrenia and healthy controls. Method: In total 23 patients with schizophrenia and 14 controls were assessed with the Karolinska Scales of Personality (KSP). A broad cognitive test programme was used, including the Wechsler Adult Intelligence Scales, the Finger-Tapping Test, the Trail Making Test, the Verbal Fluency Test, the Benton Visual Retention Test, the Wisconsin Card Sorting Test and Rey Auditory Verbal Learning Test . Results: Compared with controls, the patients exhibited prominent elevations on KSP scales measuring anxiety proneness and neuroticism (P 0.000005–0.0001), on the Detachment scale (P 0.00009) and lower value on the Socialization scale (P 0.0002). The patients also scored higher on the Inhibition of Aggression, Suspicion, Guilt and Irritability scales (P 0.002–0.03) while the remaining five scales did not differ between patients and controls. KSP anxiety-related scales correlated with the Positive and Negative Symptoms Scale (PANSS) general psychopathology subscale. Cognitive test results were uniformly lower in the patient group and correlated with PANSS negative symptoms subscale. There was no association between KSP scale scores and PANSS positive or negative symptoms. Conclusion: The patients revealed a highly discriminative KSP test profile with elevated scores in neuroticism- and psychoticism-related scales as compared to controls. Results support previous findings utilizing other personality inventories in patients with schizophrenia. Cognitive test performance correlated inversely with negative symptoms. • Cognition, Negative symptoms, Schizophrenia, Personality. Björn Mikael Nilsson, Department of Neuroscience, Psychiatry, Uppsala University, SE 751 85 Uppsala, Sweden; E-mail: [email protected]; Accepted 29 April 2015.
S
chizophrenia is a chronic disease with a highly variable lifetime course. Although successful pharmacological treatment may result in symptomatic relief from positive symptoms, the negative symptoms often remain and frequently also produce a continuous need for support to keep up basal daily activities. A relationship between severe negative symptoms and an unfavourable long-term outcome is accordingly reported in previous studies (1–3). Cognitive symptoms are also associated with a worse outcome (4). The cognitive dysfunctions in schizophrenia cover a wide span of disturbances regarding attention, working memory, information processing and executive functions (5–7). This generalized impairment also appears to be remarkably stable over time both in individuals (8) and schizophrenia © 2015 Informa Healthcare
populations (6). Cognitive impairment is thus so prominent in the clinical picture that it has been proposed to have a diagnostic value for schizophrenia (9). Furthermore, personality factors may also be related to longterm outcome in schizophrenia. Psychiatry has long searched for stable measures of personality traits that have nosological and biological relevance. Such personality traits should not be influenced by cultural or socio-economic boundaries. They should also in a predictable way wield an influence on how individuals deal with everyday challenges. From a clinical perspective, personality traits have been proposed to be of importance for the ability to cope with somatic and psychiatric diseases (10). Among the personality inventories used in psychiatric research are the Eysenck Personality DOI: 10.3109/08039488.2015.1048720
Downloaded by [Universite Laval] at 19:03 05 November 2015
B M Nilsson et al.
Questionnaire (EPQ) (11), the Temperament and Character Inventory (TCI) (12) and five-factor dimensional instruments (extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience) such as the Big Five (13) or the revised NEO Personality Inventory (NEO-PI-R) (14). Some instruments are considered to be more biologically founded and the temperament dimensions in Cloninger’s biosocial model are thus claimed to be heritable (12). The Karolinska Scales of Personality (KSP) also has its origin in biological research (15, 16). The KSP instrument was developed for the measurement of personality in relation to biological correlates with a specific purpose to recognize high-risk individuals and vulnerability factors for psychopathology. KSP was originally intended for use in both healthy individuals and in psychiatric disorders, among them schizophrenia. KSP has been used in different biological studies (17) but there are no records focusing on the KSP scales profile in patients with schizophrenia compared to controls or in relation to cognitive function. In schizophrenia, previous studies with different personality inventories have indicated the presence of stable personality traits regarding the dimensions neuroticism/harm avoidance and extraversion (18–22). In general, specific personality traits are thought to impair social functioning and the ability to cope with everyday difficulties (21). To a great extent, the ability to cope with a life-long disease, persisting symptoms and cognitive disturbances, is closely related to outcome in schizophrenia. The personality traits reported in schizophrenia, with higher levels of neuroticism and lower levels of extraversion (18, 19), have thus been associated with more avoidant and fewer problem-solving coping strategies (10). Linked to the capacity of coping is also insight, i.e. the awareness of an existing illness and the need for treatment. In schizophrenia, insight has been associated both with executive cognitive functioning and personality dimensions (23, 24). Further, the capacity for self-reflectivity and other aspects of metacognition are closely intertwined with insight and consequently proposed to be major predictors for functional outcome (25). Meta-cognition has repeatedly been associated with cognitive parameters in schizophrenia (26, 27). Another question is whether specific personality traits like schizotypy will increase the risk for schizophrenia (28). Epigenetic mechanisms may here have a regulatory function in the transformation into different phenotype outcomes regarding personality, cognition and the development of disease. Several candidate genes have thus been identified and suggested as vulnerable for epigenetic changes like DNA methylation and the risk for schizophrenia, among them the serotonin receptor TR2A gene and the brain-derived neurotrophic factor (BDNF) gene (29, 30).
2
Overall, there are a number of genetic studies using different kinds of personality assessments in schizophrenia (31, 32). Studies are fewer on personality parameters in relation to clinical psychotic symptoms (33–35) or outcome (21, 36, 37), and studies using broad neuropsychological examinations are also scarce (24). Some studies have explored a limited selection of cognitive examinations together with measurement of personality dimensions (10, 18), but to our knowledge there are no studies using the KSP, symptom assessment, and an extensive cognitive test battery in patients with schizophrenia and controls. The aim of the present study was therefore to examine personality traits, cognition and psychotic symptoms in patients with schizophrenia in comparison with a healthy control group.
Patients and methods Participants
The study was approved by the regional ethical review board in Uppsala and performed in accordance with the Declaration of Helsinki. All subjects received oral and written information about the full nature of the study before giving written consent to participate. Both newly admitted first episode patients and chronic patients aged 18–50 years, with DSM-IV diagnosed schizophrenia or schizophreniform disorders were recruited consecutively. The participants are a subset of a larger research sample recruited in Uppsala, Sweden, from which cognition in electrodermal non-responders is also reported (38). In total, 30 patients and 17 controls were recruited originally (39). From this group, seven patients and three controls were lost for follow-up with personality examinations, in most cases due to non-compliance. The present sample thus comprised 23 patients and 14 controls. Four of the patients were antipsychotic naïve and 19 patients were treated with second-generation antipsychotics. The healthy controls were recruited through a newspaper advertisement.
Procedures The personality assessments and the cognitive examinations were carried out in a stable phase of illness in the patients. All participants were assessed with the Karolinska Scales of Personality and the Positive and Negative Syndrome Scale (PANSS). A broad cognitive test battery was also administered. While all patients performed the Halstead Reitan Finger tapping test (FTT), the Trail Making Test (TMT) and Benton’s Visual Retention Test (BVRT), there were some dropouts on other tests. Two patients did not perform the Wechsler Adult Intelligence Scale (WAIS) and one patient was administered a limited subset of WAIS scales due to language difficulties. Two other patients did not fulfil the Wisconsin Card Sorting Test (WCST) or the Verbal Fluency Test. Five patients NORD J PSYCHIATRY·EARLY ONLINE·2015
Personality and cognition in schizophrenia
Downloaded by [Universite Laval] at 19:03 05 November 2015
did not participate in the Rey Auditory Verbal Learning Test (RAVLT). The controls completed all tests. All participants were examined with PANSS (40), a modified Extrapyramidal Symptom Rating Scale (ESRS) (41) and Strauss and Carpenter’s Prognostic Scale for outcome (42). ESRS scores were the sum points on ESRS subscales I–IV, consisting of a questionnaire for extrapyramidal and movement disorders plus examinations for Parkinsonism, akathisia, dystonia and dyskinesia. Items V–VIII in the original ESRS scale are Clinical Global Impression scales of the same symptoms and were omitted from this study. The SCPS items used five response steps from 0–4 and covered the original four items: hospital admissions, social contacts, work, and symptoms. Characteristics of patients and controls are exhibited in Table 1.
Personality assessment KSP consists of 15 scales with 135 items altogether. The KSP scales are Somatic Anxiety (SA), Psychic Anxiety (PA), Muscular Tension (MT), Psychasthenia (PSA), Impulsiveness (IMP), Monotony Avoidance (MA), Socialization (SO), Verbal Aggression (VA), Indirect Aggression (INDA), Irritability (IRR), Suspicion (SU), Guilt (GU), Inhibition of Aggression (INHA), Social Desirability (SD) and Detachment (DET). For a description of the personalities gaining high scores in the different KSP scales see Gustavsson et al. (43). KSP items use four response steps from “does not apply at all” to “applies completely”. The point responses were transferred to T-scores with a mean of 50 and standard deviation (SD) 10. KSP was administered as a self-report instrument. Also included in the analysis were four KSP factors used in several genetic studies (44); neuroticism (SA, PA, Table 1. Characteristics of patients and controls.
Gender: male/female Age in years Education: 12 years/ 12 years Duration of illness in years Antipsychotic medication in mg‡ PANSS total PANSS positive subscale PANSS negative subscale PANSS general subscale Strauss–Carpenter scale ESRS subscales I-IV sum
Patients n 23
Controls n 14
P-value
16/7 32.0 (8.9) 6/17 7.5 (8.1) 301.7 (174.7) 68.8 (10.5) 15.6 (4.4) 20.0 (5.8) 33.2 (4.9) 9.1 (3.2) 13.1 (10.4)
9/5 33.3 (8.4) 2/12 – – 32.6 (1.7) 7.8 (0.9) 7.4 (0.8) 17.4 (1.0) 15.7 (0.7) 1.1 (1.4)
NS* NS NS† – – ND ND ND ND ND ND
Mann Whitney U-tests, means (and standard deviation) unless otherwise noted. ESRS, Extrapyramidal Symptom Rating Scale; ND, not determined (p 0.00001); NS, not significant; PANSS, Positive and Negative Syndrome Scale. *Chi-squared test. †Fisher’s exact test. ‡Chlorpromazine equivalents. NORD J PSYCHIATRY·EARLY ONLINE·2015
MT, PSA, INHA, GU and SO), extraversion (IMP and MA), psychoticism (DET and SU) and non-conformity (SD, INDA, VA and IRR). Factor analyses of KSP scales in different populations have yielded slightly different factor solutions. The present solution goes back to the factor analysis by Gustavsson et al. (45) and has been used in several studies with minor modifications (46).
Cognitive testing Cognitive testing was performed during 2–3 sessions depending on the participants’ cognitive speed and motivation. The tests used in the study were chosen to examine relevant cognitive functions in patients newly diagnosed with schizophrenia and to cover the following cognitive domains: verbal comprehension and fluency, short-/long-term memory, perceptual organization, psychomotor function, executive function and processing speed. The revised WAIS (WAIS-R) include six verbal scales: Information, Digit Span, Vocabulary, Arithmetic, Comprehension, Similarities. Further, WAIS-R comprises five performance scales: Picture Completion, Picture Arrangement, Block Design, Object Assembly and Digit Symbol (47, 48). Some of the subtests are related to verbal comprehension (Information, Vocabulary, Similarities and Comprehension), others to short-term memory (Digit Span, Arithmetic and Digit Symbol) and perceptual organization (Picture Completion, Picture Arrangement, Block Design and Object Assembly). Based on test results, verbal (IQV), performance (IQP) and full-scale intelligence quotient (IQ) can be calculated. WAIS raw scores were transformed to age-adjusted scores by the means of Swedish normative data. The RAVLT uses a simple word-list paradigm and measures immediate memory span, learning and retention (48). The Controlled Oral Word Association Test (COWAT) is a verbal fluency test measuring the number of words associated with specific letters during a 3-min test period (48). The Halstead Reitan FTT is a psycho-motor test that measures motor speed and dexterity (48, 49). The Trail-Making Test A (TMT A) and B (TMT B) evaluate conceptual and visuomotor tracking and involve motor speed and attention as well as executive function. Time to completion is the primary measure in TMT (48, 50). The WCST assesses abstract reasoning, concept formation and flexibility. WCST has been useful in analyses of disordered executive function in various psychiatric and neurological diseases. A number of scoring alternatives are available. In schizophrenia the ability for shift-making and cognitive endurance are crucial for executive function in everyday living. The number of perseverative errors, non-perseverative errors and categories achieved are presented here (48, 51). The BVRT is a visual recall test that implies drawing of geometrical figures after 10-s exposure. Both number of correct designs and errors are scored (48).
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Statistical analysis
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Scores on KSP, COWAT, FTT, TMT and WCST were transformed to age- and gender-adjusted T scores with a mean of 50 and SD of 10. The T-score transformation on “inverted” tests, like WCST errors or TMT, also results in a homogenous data interpretation; lower score represents worse performance. Mann-Whitney U-tests were used for group comparisons. P-values of 0.05 were considered to indicate a significant difference. Dichotomous variables such as gender were analysed with Chisquared tests. When the number of observations were low ( 5), Fisher’s exact test was used. Correlation analysis was performed with the Spearman rank order correlation. All statistical calculations were performed with STASTISTICA version 12.0 software.
Results
Personality KSP scores are shown in Table 2. The patients exhibited high scores in four scales (SA, PA, MT, PSA) related to factor neuroticism as well as low scores in SO also belonging to the same factor. The scale DET was also elevated in the patient group. The differences between groups on some scales, e.g. IRR, may in part be due to relatively lower scores in the control group. Taken Table 2. Karolinska Scales of Personality. Differences between patients and controls. Mann Whitney U-tests, means (and standard deviation). Patients n 23 Somatic Anxiety Psychic Anxiety Muscular Tension Psychasthenia Impulsiveness Monotony Avoidance Socialization Verbal Aggression Indirect Aggression Irritability Suspicion Guilt Inhibition of Aggression Social Desirability Detachment Factor 1. Extraversion* Factor 2. Neuroticism† Factor 3. Psychoticism‡ Factor 4. Non-conformity§
60.6 60.5 57.4 64.1 45.7 46.3 39.4 42.6 49.1 48.6 52.6 51.2 58.7 57.0 57.1 46.1 56,0 54,9 49,3
(10.4) (15.0) (10.1) (13.9) (13.0) (14.3) (12.1) (12.1) (7.7) (12.3) (10.2) (11.0) (11.1) (12.7) (12.7) (11.6) (6.3) (9.5) (5.0)
Controls n 14 40.8 40.1 42.2 40.4 50.6 52.0 56.0 45.6 47.1 38.8 42.7 43.4 47.9 56.0 40.4 51.3 44.5 41.6 46.9
(5.3) (5.9) (6.7) (8.6) (9.4) (7.5) (6.6) (8.3) (8.5) (6.1) (6.3) (5.4) (7.6) (8.1) (6.3) (7.8) (3.6) (5.9) (4.2)
P-value 0.000005 0.00004 0.0001 0.000009 NS NS 0.0002 NS NS 0.01 0.002 0.03 0.006 NS 0.00009 NS 0.0000001 0.00004 NS
NS, not significant. *Impulsiveness, Monotony Avoidance. †Somatic Anxiety, Psychic Anxiety, Muscular Tension, Psychasthenia, Inhibition of Aggression, Guilt, Socalization. ‡Detachment, Suspicion. §Indirect Aggression, Verbal Aggression, Irritability, Social Desirability.
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together, the results constitute the discriminative profile exhibited in Fig. 1 which depicts the differences in T-scores between patients and controls (mean T-score in patients minus mean T-score in controls for every KSP scale). There was no correlation between KSP scales and demographic data in the two groups. In the patients, KSP SA, MT and DET correlated with the PANSS general psychopathology subscale (r 0.57, P 0.004, r 0.58, P 0.004 and r 0.52, P 0.010 respectively). The KSP scales correlated with few cognitive parameters in the patient group; IRR with IQV (r 0.47, P 0.04), DET and SU with WCST non-perseverative errors (r 0.54, P 0.01 and r 0.44, P 0.04 respectively) and SA with Rey immediate recall (r 0.49, P 0.04). When the four-factor model (neuroticism, extraversion, psychoticism and non-conformity) was applied, pronounced divergences between patients and controls were seen in neuroticism and psychoticism factors. There were no correlations between the four factors either in the patient or in the control group. The overlapping correlations between separate scales and other factors were few in the patient group. PSA thus correlated with the nonconformity factor (r 0.63, P 0.002). Further, SA and SO correlated with the psychoticism factor (r 0.48, P 0.02 and r 0.56, P 0.005 respectively). The psychoticism factor also correlated with WCST nonperseverative errors (r 0.60, P 0.004) in the patients. There were no other correlations between any KSP scale or factor and any cognitive measure. In the control group there were significant inverse correlations between KSP subscale DDET and TMT A (r 0.67, P 0.008) as well as between DDET and COWAT (r 0.67, P 0.009).
Cognition The patients exhibited lower results than the controls on all administered tests (Table 3). Highly significant differences were seen in some of the WAIS verbal subtests, WAIS Digit Symbol Coding and TMT B. There were expected correlations between different cognitive instruments both in patients and controls. In the patients, PANSS negative symptoms exhibited the most consistent pattern of correlation with cognitive parameters (Table 3). Digit Symbol Coding, TMT B along with Rey learning tests thus showed the highest correlation, but all cognitive tests except Information, Vocabulary, Object Assembly, WCST non-perseverative errors and the psychomotor FTT tests correlated with PANSS negative symptoms (Table 3). As a rudimentary measure of the insight dimension, the PANSS item G12, Lack of Judgement and Insight, was analysed separately regarding possible association to personality or cognitive parameters in the patients. No such correlations were found. Regarding demographic NORD J PSYCHIATRY·EARLY ONLINE·2015
Personality and cognition in schizophrenia Karolinska Scales of Personality Differences between Patients and Controls SA
p=
