The relation between neurocognitive dysfunction and impaired insight in patients with schizophrenia

Available online at

www.sciencedirect.com European Psychiatry 24 (2009) 239e243

Original article

The relation between neurocognitive dysfunction and impaired insight in patients with schizophrenia Viktoria Simon a, Marc De Hert b,*, Martien Wampers b, Joseph Peuskens b, Ruud van Winkel b,c a

Semmelweis University Budapest, Department of Psychiatry and Psychotherapy, Balassa u. 6., 1083 Budapest, Hungary b University Psychiatric Center, Catholic University Leuven, Leuvensesteenweg 517, 3070 Kortenberg, Belgium c Department of Psychiatry and Neuropsychology, EURON, South Limburg Mental Health Research and Teaching Network, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands Received 26 March 2008; received in revised form 12 October 2008; accepted 16 October 2008 Available online 13 December 2008

Abstract Objectives. e The present study aimed to (i) evaluate the association between insight and measures of executive functions and working memory in a sample of 132 patients with schizophrenia and (ii) to explore to what proportion neurocognitive dysfunction contributed to the variance in insight after controlling for symptomatology. Methods. e Subjects were evaluated with a standardized neurocognitive test battery and a semi-structured interview, the Psychosis Evaluation tool for Common use by Caregivers (PECC). PECC, apart from evaluating symptoms and side-effects, measures insight on a 4-point scale by two of its dimensions: awareness of having a mental illness (AMI) and awareness of having symptoms attributed to a mental illness (ASAMI). Executive functioning was measured by the Wisconsin Card Sort Test (WCST) and the Trail Making B (TMB). Working memory was measured by the Letter Number Sequencing (LNS) test from the Wechsler Adult Intelligence Scale (WAIS). Results. e Only one significant association was found after correction for multiple testing, between WCST categories completed and AMI (r ¼ 0.29, p ¼ 0.0006). WCST categories completed explained only 7.9% of the variance in AMI, while symptomatology explained 20% of variance in AMI and 16.5% of variance in ASAMI. Conclusions. e The current results show a significant but subtle association with the WCST, which is in agreement with earlier literature. No other associations between cognitive functioning and insight were found. In general, these findings seem to suggest that factors other than cognition have a greater impact on insight in patients with schizophrenia. Ó 2008 Elsevier Masson SAS. All rights reserved. Keywords: Insight; Executive functions; Working memory; Schizophrenia

1. Introduction Lack of insight, one of the most common features in schizophrenia, is a widely studied phenomenon and considered a multidimensional construct [5,26]. The most accepted dimensions of insight are: (1) awareness of suffering from a mental illness, (2) awareness of specific signs and symptoms * Corresponding author. University Psychiatric Center, Catholic University Leuven, Leuvensesteenweg 517, 3070 Kortenberg, Belgium. Tel.: þ32 2 758 05 11; fax: þ32 2 759 98 78. E-mail address: [email protected] (M. De Hert). 0924-9338/$ - see front matter Ó 2008 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.eurpsy.2008.10.004

of the disorder, (3) the attribution of symptoms to the mental illness, (4) awareness of need for treatment and (5) understanding the social consequences of the mental illness [3]. During the past decades the operational definition and measurement tools of insight have improved, as well as the understanding of its clinical importance [4,7,21]. Nevertheless, the underlying etiological mechanisms remain poorly understood. A meta-analysis of 52 studies reported an overall modest, but significant negative relationship between insight and both positive and negative symptoms, whereas the relationship between depression and insight showed a modest but significant positive relationship [26].

240

V. Simon et al. / European Psychiatry 24 (2009) 239e243

A body of literature deals with the possible relationship between specific neurocognitive functions and insight. Some of the studies reported a significant association between impaired insight and executive functioning [12,20,22,25,29], memory [18,27,33], or attention [21]. Other studies, however, did not find significant associations with either executive functioning [9,14], memory [2,8,29] or attention [29]. The most widely used measure of executive functioning is the Wisconsin Card Sort Test (WCST). Many studies have dealt with the possible association between the WCST and impaired insight. For example, Young and colleagues found a significant association between WCST results and both unawareness of mental illness and symptom misattribution in 31 chronic schizophrenia patients [35]. Similar results were found in subjects with chronic schizophrenia who had just recovered from an acute psychotic episode [33], in acutely psychotic patients [12] and in first-episode patients [18]. Furthermore, Lysaker and Bell administered the WCST repeatedly over a 1year period in 29 patients with impaired insight and 63 patients with unimpaired insight and found that patients with impaired insight showed a consistently poorer performance, especially on perseverative errors and categories completed [20]. Thus, the results of WCST were most consistently reported as significantly associated with impaired insight [1], which is in agreement with imaging studies suggesting that executive functioning may be involved in the etiology of lack of insight [30,31]. In a recent meta-analysis of 33 studies, a small but significant positive relationship was found between insight and general cognitive functioning [1]. Specifically, Intelligence Quotient (IQ), results of the WCST, executive functions in general (including measurements with WCST), and memory were found to be associated with insight in schizophrenia [1]. Two studies focused on explained variance of cognitive measures on insight and found that, although Trail Making A, B and WCST were associated with insight, these associations did not significantly contribute to the variance in insight [9,17]. These studies, however, were conducted in samples of only 74 and 58 patients, respectively. The current study, therefore, aimed to assess this association in a relatively large sample (n ¼ 132) of patients with schizophrenia. Second, we also aimed to explore to what proportion neurocognitive dysfunction contributed to the variance in insight in this sample, after controlling for symptomatology.

schizoaffective disorder or schizophreniform disorder based on DSM-IV, as established by their treating psychiatrist. Basic demographic data are summarized in Table 1. Our sample is a naturalistic hospital based sample, comprised of patients with a wide range of actual severity of the symptoms (Table 2). 2.2. Assessment methods PECC, next to evaluating symptoms and side-effects, measures insight on a 4-point scale by two of its dimensions: awareness of having a mental illness (AMI) and awareness of having symptoms attributed to a mental illness (ASAMI). A higher score on the insight scale refers to lower level of insight (1 ¼ good insight, 2 ¼ insight in the majority of symptoms, 3 ¼ insight in the minority of symptoms, 4 ¼ insight is absent). PECC evaluates 20 symptom items on a 7-point scale, resulting in a range of possible symptom score of 20e140. Symptoms are grouped in 5 factors: positive (hallucinations, delusions, unusual thought content, grandiosity), negative (poor rapport, passive/apathetic withdrawal, blunted affect, motor retardation), depressive (anxiety, depression, guilt feelings, somatic concern), cognitive (poor attention, disorientation, difficulty with abstract thinking, conceptual disorganization) and excitatory (poor impulse control, lack of cooperation, hostility, excitement). PECC is a relatively new assessment tool. Validation results suggest that it can be successfully used for the evaluation of symptoms in schizophrenia (Pearson’s correlation with PANSS symptoms in total: 0.90) [11]. Executive functioning was measured by the Wisconsin Card Sort Test (WCST) [16] and the Trail Making B (TMB) test [28]. Working memory was measured by the Letter Number Sequencing (LNS) test from the Wechsler Adult Intelligence Scale (WAIS) [34]. Patients were assessed by trained psychologists blinded for the clinical ratings of the patients. The LNS was completed by 131 (1 missing observation) and the TMB by 126 patients (6 missing observations). The study was approved by the local ethics committees and all subjects provided written informed consent. 2.3. Statistical analysis Descriptive statistics were computed for basic demographic and clinical variables. The associations between neurocognitive and insight measures were evaluated through

2. Method 2.1. Study sample Between 2000 and 2006, 132 inpatients were evaluated in the University Psychiatric Center of the Catholic University of Leuven (Belgium) with a standardized neurocognitive test battery and a semi-structured interview, the Psychosis Evaluation tool for Common use by Caregivers (PECC) (see details in Refs. [10,11]). Assessment dates of the neurocognitive testing and the PECC interview were no longer than 14 days apart. All participants were diagnosed with schizophrenia,

Table 1 Descriptive and demographic data of the sample (n ¼ 132). Age (mean, SD) Gender n (%): Male Female Educational level n (%): Primary school Lower secondary school High school Higher education/University

29.7 (8.9) 89 (67.4%) 43 (32.6%) 6 42 64 20

(4.6%) (31.8%) (48.5%) (15.1%)

V. Simon et al. / European Psychiatry 24 (2009) 239e243 Table 2 Mean scores of the examined variables in the sample (n ¼ 132). Variables

Mean (SD)

PECC AMI score

2.7 (1.0)

Distribution of insight item scores 1 ¼ Good insight 2 ¼ Insight into the majority of symptoms 3 ¼ Insight into the minority of symptoms 4 ¼ Absent insight

11% 33% 32% 24%

PECC ASAMI score

2.4 (1.0)

Distribution of insight item scores 1 ¼ good insight 2 ¼ insight into the majority of symptoms 3 ¼ insight into the minority of symptoms 4 ¼ absent insight

17% 38% 29% 16%

PECC total symptom score PECC positive symptom score PECC negative symptom score PECC depressive symptom score PECC cognitive symptom score PECC excitatory symptom score WCST perseverative errors WCST categories completed LNS TMT B

46.2 (12.0) 8.5 (3.9) 10.8 (4.4) 10.4 (3.7) 7.7 (3.5) 8.3 (3.6) 10.9 (7.2) 2.6 (1.6) 8.3 (3.3) 88.5 (63.5)

AMI: awareness of having a mental illness, and ASAMI: awareness of having symptoms attributable to a mental illness.

Pearson correlations. Bonferroni correction was used to control for multiple testing. In a previous study a regression model based on selected symptom scores was constructed for each insight item [32]. Both AMI- and ASAMI-level were predicted based on the PECC-scores for delusions, hallucinations, poor rapport, guilt feelings, difficulty in abstract thinking, passiveeapathic social withdrawal, megalomanic thoughts, and depression. This model was expanded for both AMI and ASAMI with an additional symptom item that differed for both insight items, i.e., hostility and disorganised thinking, respectively. In the present study, this regression model was expanded with the scores obtained on the neurocognitive tasks significantly associated with AMI and/or ASAMI, to evaluate the proportion of variance in AMI and ASAMI explained by the above mentioned regressors. 3. Results The sample consisted mostly of male patients (Table 1). Their mean cognitive test scores, PECC total symptom scores, PECC symptom cluster scores and PECC insight scores are summarized in Table 2. Among the examined cognitive variables only ‘WCST perseverative errors’ and ‘WCST categories completed’ correlated significantly with awareness of having a mental illness (AMI), while only LNS and ‘WCST categories completed’ correlated significantly with awareness of having symptoms attributable to a mental illness (ASAMI). However, after correcting for multiple testing, only the association

241

between ‘WCST categories completed’ and AMI remained significant (Table 3). ‘WCST categories completed’, the only cognitive variable that was significantly associated with insight, specifically with awareness of having a mental disorder, explained only 7.9% of the variance in AMI (F(1,130) ¼ 11.23, p ¼ 0.0011). Symptomatology explained 20% of variance in AMI (F(9,122) ¼ 4.6, p < 0.0001, R-Square ¼ 0.25, Adj R-Square ¼ 0.19) and 16.5% of variance in ASAMI (F(9,122) ¼ 3.87, p ¼ 0.0002, R-Square ¼ 0.22, Adj R-Square ¼ 0.16) in the present sample (Table 4). After adding ‘WCST categories completed’ to this model, the explained variance of AMI marginally increased to 22.5% (F(10,121) ¼ 4.81, p < 0.0001, R-Square ¼ 0.28, Adj RSquare ¼ 0.22) (Table 5). 4. Discussion The present study did not show significant associations between the examined cognitive measures and insight items after controlling for multiple testing, except for a significant but small association between ’WCST categories completed’ and AMI. This finding is in line with other findings in the literature, where most consistent findings were reported on the association of the WCST with impaired insight [specifically perseverative errors and/or categories completed] [1]. The current study did not find an association between working memory and insight variables. Associations between memory and insight were reported previously by some authors [15,18,27,33], whereas others were unable to find an association [2,8,29]. A possible explanation for the inconsistencies regarding the association between cognition and insight may be situated in the application of different insight measures. While some studies apply a single insight variable [e.g., provided by PANSS insight score] [2,20], other studies used different insight measures evaluating two or more dimensions of insight [9,12,17,25,29,33]. Furthermore, the investigated samples differ in sample size and composition, and clinical status of the subjects [33]. Although the present study has several limitations such as an inpatient sample, retrospective data analysis and insight measured by only two of its dimensions, our results showed that executive functions and working memory were not major determinants of insight. However, 16e20% of the variance in insight was attributable to the effect of symptomatology. These reported findings are in line with several previous findings in the literature [2,8,9,13,17,18,26]. Table 3 Correlations between insight and cognitive measures. Cognitive measures

AMI

p

ASAMI

p

LNS WCST categories completed WCST perseverative errors TMT B

0.10 0.28 0.16 0.10

0.2308 0.0011 0.0620 0.2620

0.14 0.13 0.10 0.1

0.1012 0.1346 0.2599 0.2822

AMI: awareness of having a mental illness, and ASAMI: awareness of having symptoms attributable to a mental illness.

V. Simon et al. / European Psychiatry 24 (2009) 239e243

242

Table 4 Result of the regression model I. Symptomatology. Predictors

AMI

Delusions Poor rapport Guilt feelings Abstract thinking Passive/apathic social withdrawal Grandiosity Depression Hostility Hallucinations Disorientation

Parameter Estimate

p

0.09 0.08 0.03 0.20 0.06 0.07 0.01 0.02 0.10 e

0.1538 0.3016 0.5736 0.0014 0.4515 0.3744 0.8252 0.7750 0.1056 e

Standard Error

t-Value

0.06 0.08 0.07 0.06 0.08 0.08 0.08 0.06 0.07 e

1.44 1.04 0.56 3.27 0.76 0.89 0.22 0.29 1.63 e

ASAMI Parameter Estimate

p

0.11 0.08 0.07 0.08 0.03 0.09 0.009 e 0.08 0.09

0.0446 0.3272 0.1977 0.1597 0.6415 0.1934 0.9685 e 0.1592 0.4034

Standard Error

t-Value

0.05 0.07 0.06 0.06 0.07 0.07 0.06 e 0.06 0.12

2.03 0.98 1.30 1.41 0.47 1.31 0.15 e 1.42 0.84

AMI: awareness of having a mental illness, and ASAMI: awareness of having symptoms attributable to a mental illness.

It has been already argued that a complex system of different, overlapping variables may underlie impaired insight and that these variables may contribute to a different extent to specific dimensions of poor insight. Results from the current study and from earlier work suggest that neurocognitive dysfunction may only play a limited role in the etiology of impaired insight of patients with schizophrenia. Bora et al. in a recent study investigated the relationship between insight and Theory of Mind [ToM] tasks [6], which refers to the person’s ability to understand the mental states of others (like beliefs, intentions and feelings). Second order ToM dysfunction (the ability to understand that someone else thinks that a third person believes something) was reported as a prominent predictor of global insight deficits and symptom misattribution. Furthermore, second order ToM deficits explained a substantial proportion (over 22%) of the variance in insight ratings. Additionally, WCST perseverative errors did not contribute significantly to prediction of insight scores but was correlated strongly to second order ToM tasks [6]. Thus, one way to understand the link between executive function and insight is that it does not reflect a direct link. Neurocognitive dysfunction may not cause poor insight, but executive function deficits may instead limit other capacities needed for insight such as ToM [6,24] and metacognition, including the ability to be aware of one’s own thoughts and feelings [19,23]. Table 5 Result of the regression model II. Symptomatology and WCST categories completed. Predictors

Delusions Poor rapport Guilt feelings Abstract thinking Passive/apathic social withdrawal Grandiosity Depression Hostility Hallucinations WCST categories completed

AMI Parameter Estimate

p

Standard Error

t-Values

0.07 0.09 0.02 0.17 0.06 0.08 0.04 0.04 0.10 0.13

0.2147 0.2545 0.7285 0.0107 0.4328 0.3281 0.6107 0.6107 0.1067 0.0249

0.06 0.08 0.06 0.06 0.08 0.08 0.07 0.08 0.06 0.06

1.25 1.14 0.35 2.59 0.79 0.98 0.54 0.51 1.63 2.27

AMI: awareness of having a mental illness.

5. Conclusion To conclude, the current results show a subtle, but significant association with the WCST, which is in accordance with previous findings. No other associations between cognitive functioning and insight were found. In general, these findings seem to suggest that factors other than cognition have a greater impact on insight in patients with schizophrenia. Future studies focusing on impaired insight may benefit from investigating other variables, such as personality and social factors (as psychological defensiveness, harm avoidance, reward dependence, concerns about judgement of the society), as well as metacognition. References [1] Aleman A, Agrawal N, Morgan KD, David AS. Insight in psychosis and neuropsychological function: meta-analysis. Br J Psychiatry 2006;189: 204e12. [2] Aleman A, de Haan EH, Kahn RS. Insight and neurocognitive function in schizophrenia. J Neuropsychiatry Clin Neurosci 2002;14(2):241e2. [3] Amador X, David A. Insight and psychosis. New York: Oxford University Press; 1998. [4] Amador XF, Flaum M, Andreasen NC, Strauss DH, Yale SA, Clark SC, et al. Awareness of illness in schizophrenia and schizoaffective and mood disorders. Arch Gen Psychiatry 1994;51(10):826e36. [5] Amador XF, Gorman JM. Psychopathologic domains and insight in schizophrenia. Psychiatr Clin North Am 1998;21(1):27e42. [6] Bora E, Sehitoglu G, Aslier M, Atabay I, Veznedaroglu B. Theory of mind and unawareness of illness in schizophrenia: is poor insight a mentalizing deficit? Eur Arch Psychiatry Clin Neurosci 2007;257(2):104e11. [7] Buckley PF, Wirshing DA, Bhushan P, Pierre JM, Resnick SA, Wirshing WC. Lack of insight in schizophrenia: impact on treatment adherence. CNS Drugs 2007;21(2):129e41. [8] Carroll A, Fattah S, Clyde Z, Coffey I, Owens DG, Johnstone EC. Correlates of insight and insight change in schizophrenia. Schizophr Res 1999;35(3):247e53. [9] Collins AA, Remington GJ, Coulter K, Birkett K. Insight, neurocognitive function and symptom clusters in chronic schizophrenia. Schizophr Res 1997;27(1):37e44. [10] De Hert M, van Winkel R, Wampers M, Kane J, van Os J, Peuskens J. Remission criteria for schizophrenia: evaluation in a large naturalistic cohort. Schizophr Res 2007;92(1e3):68e73. [11] De Hert M, Wampers M, Thys E, Wieselgren IM, Lindstrom E, Peuskens J. Validation study of PECC (Psychosis Evaluation tool for Common use by Caregivers): interscale validity and inter-rater reliability. Int J Psych Clin Pract 2002;6:135e40.

V. Simon et al. / European Psychiatry 24 (2009) 239e243 [12] Drake RJ, Lewis SW. Insight and neurocognition in schizophrenia. Schizophr Res 2003;62(1e2):165e73. [13] Freudenreich O, Deckersbach T, Goff DC. Insight into current symptoms of schizophrenia. Association with frontal cortical function and affect. Acta Psychiatr Scand 2004;110(1):14e20. [14] Goldberg RW, Green-Paden LD, Lehman AF, Gold JM. Correlates of insight in serious mental illness. J Nerv Ment Dis 2001;189(3):137e45. [15] Goodman C, Knoll G, Isakov V, Silver H. Insight into illness in schizophrenia. Compr Psychiatry 2005;46(4):284e90. [16] Heaton R. Wisconsin card sort test manual. Odessa: Psychological Assessment Resources; 1981. [17] Kemp R, David A. Psychological predictors of insight and compliance in psychotic patients. Br J Psychiatry 1996;169(4):444e50. [18] Keshavan MS, Rabinowitz J, DeSmedt G, Harvey PD, Schooler N. Correlates of insight in first episode psychosis. Schizophr Res 2004; 70(2e3):187e94. [19] Koren D, Seidman LJ, Poyurovsky M, Goldsmith M, Viksman P, Zichel S, et al. The neuropsychological basis of insight in first-episode schizophrenia: a pilot metacognitive study. Schizophr Res 2004;70(2e3): 195e202. [20] Lysaker P, Bell M. Insight and cognitive impairment in schizophrenia. Performance on repeated administrations of the Wisconsin Card Sorting Test. J Nerv Ment Dis 1994;182(11):656e60. [21] Lysaker P, Bell M. Work rehabilitation and improvements in insight in schizophrenia. J Nerv Ment Dis 1995;183(2):103e6. [22] Lysaker PH, Bell MD, Bryson G, Kaplan E. Neurocognitive function and insight in schizophrenia: support for an association with impairments in executive function but not with impairments in global function. Acta Psychiatr Scand 1998;97(4):297e301. [23] Lysaker PH, Carcione A, Dimaggio G, Johannesen JK, Nicolo G, Procacci M, et al. Metacognition amidst narratives of self and illness in schizophrenia: associations with neurocognition, symptoms, insight and quality of life. Acta Psychiatr Scand 2005;112(1):64e71. [24] Lysaker PH, Daroyanni P, Ringer JM, Beattie NL, Strasburger AM, Davis LW. Associations of awareness of illness in schizophrenia

[25]

[26] [27]

[28]

[29]

[30]

[31]

[32]

[33]

[34] [35]

243

spectrum disorder with social cognition and cognitive perceptual organization. J Nerv Ment Dis 2007;195(7):618e21. McEvoy JP, Hartman M, Gottlieb D, Godwin S, Apperson LJ, Wilson W. Common sense, insight, and neuropsychological test performance in schizophrenia patients. Schizophr Bull 1996;22(4):635e41. Mintz AR, Dobson KS, Romney DM. Insight in schizophrenia: a metaanalysis. Schizophr Res 2003;61(1):75e88. Mutsatsa SH, Joyce EM, Hutton SB, Barnes TR. Relationship between insight, cognitive function, social function and symptomatology in schizophrenia: the West London first episode study. Eur Arch Psychiatry Clin Neurosci 2006;256(6):356e63. Reitan RM. Ward Halstead’s contributions to neuropsychology and the HalsteadeReitan Neuropsychological Test Battery. J Clin Psychol 1994; 50(1):47e70. Rossell SL, Coakes J, Shapleske J, Woodruff PW, David AS. Insight: its relationship with cognitive function, brain volume and symptoms in schizophrenia. Psychol Med 2003;33(1):111e9. Sapara A, Cooke M, Fannon D, Francis A, Buchanan RW, Anilkumar AP, et al. Prefrontal cortex and insight in schizophrenia: a volumetric MRI study. Schizophr Res 2007;89(1e3):22e34. Shad MU, Muddasani S, Prasad K, Sweeney JA, Keshavan MS. Insight and prefrontal cortex in first-episode Schizophrenia. Neuroimage 2004; 22(3):1315e20. Simon V, De Hert M, Wampers M, Peuskens J, van Winkel R. An 18month prospective study of associations between insight and symptoms in a large sample of patients with schizophrenia. Schizophr Res 2008; 102(S2):228. Smith TE, Hull JW, Israel LM, Willson DF. Insight, symptoms, and neurocognition in schizophrenia and schizoaffective disorder. Schizophr Bull 2000;26(1):193e200. Wechsler D. Wechsler adult intelligence scale e revised. New York: The Psychological Corporation; 1981. Young DA, Davila R, Scher H. Unawareness of illness and neuropsychological performance in chronic schizophrenia. Schizophr Res 1993;10(2):117e24.