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King's College London, Department of Psychology, Institute of Psychiatry, London
Division of Clinical Psychology, University of Liverpool
King's College London, Department of Psychology, Institute of Psychiatry, London, UK
Correspondence: Dr Emmanuelle Peters, King's College London, Institute of Psychiatry, Department of Psychology (PO77), 16 De Crespigny Park, Denmark Hill, London SE5 8AF, UK. Email: e.peters{at}iop.kcl.ac.uk
Funding detailed in Acknowledgements.
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMETHODRESULTSDISCUSSIONACKNOWLEDGMENTSREFERENCES |
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Aims To investigate the relationships between insight and IQ, depression, and self-esteem.
Method Correlations between self-reported and observer-rated insight, and measures of IQ, depression and self-esteem were examined in 67 people with psychosis.
Results Better self-reported insight was associated with higher IQ and poorer self-esteem, but not depression. There was some evidence for a curvilinear relationship between IQ and self-reported insight, specifically the `awareness of illness' dimension, which survived correction for symptom variables.
Conclusions The relationship between insight and IQ might reflect both the basis of insight in intellectual ability and the influence of a psychological mechanism that preserves self-esteem.
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMETHODRESULTSDISCUSSIONACKNOWLEDGMENTSREFERENCES |
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METHOD |
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Assessments
Insight was assessed using the self-report Insight Scale
(Birchwood et al,
1994), which measures three dimensions of insight: awareness of
illness (2 items), awareness of symptoms (2 items) and awareness of the need
for treatment (4 items). Each sub-scale is given equal weight when calculating
the total score. Item 4 (`My stay in hospital is necessary') was excluded
because all participants were out-patients. The remaining three items from the
`awareness of the need for treatment' dimension were used to calculate a score
for this subscale with equal weight to the other two sub-scales, allowing a
total score to be calculated which has the same range (0–12) as the full
Insight Scale. Higher scores indicate better insight.
The PANSS was used to assess positive, negative and general symptoms as part of the randomised controlled trial, and the PANSS G12 item was also used as an observer-rated measure of insight. Higher scores on the G12 item indicate poorer insight. Current IQ was measured using the Quick Test (Ammons & Ammons, 1962), a picture vocabulary test consisting of 50 items. Self-esteem was assessed using the Rosenberg Self-Esteem Scale (Rosenberg, 1965), a 10-item self-report questionnaire (higher scores indicate poorer self-esteem). Level of current depressive symptomatology was assessed using the Beck Depression Inventory (BDI; Beck et al, 1961), a 21-item self-report questionnaire. These measures were selected for their previous use in published studies of people with psychosis and their relatively brief administration time as part of an extensive clinical assessment.
Data analysis
Linear relationships between insight scores and other variables were
examined using Pearson's correlations. Following Startup
(1996), the possibility of
quadratic relationships between insight and IQ was investigated using
hierarchical regression analyses in which IQ was treated as the dependent
variable and insight score (either Insight Scale or PANSS G12 item) as a
predictor variable. The insight score was first entered into the regression to
test for a linear relationship, followed by the square of the insight score to
test for a quadratic relationship.
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RESULTS |
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The mean total Insight Scale score of 8.5 was comparable to that of the in-patient sample (at discharge) on which the scale was originally standardised (mean 8.1; Birchwood et al, 1994). Splitting our sample according to the cut-off score of 9 for good insight which was recommended in the original study (Birchwood et al, 1994), 30 individuals (44.8%) would be classified as having poor insight, whereas 37 (55.2%) would be classified as having good insight. This suggests that in our sample insight was slightly lower than in a recent neuropsychological study which utilised the Insight Scale (30% with poor insight; Donohoe et al, 2005). As expected, the total Insight Scale and PANSS G12 measures, which are scored in opposite directions, were highly negatively correlated (r=-0.646, P<0.001).
Self-reported insight
Total Insight Scale score was correlated with higher IQ (r=0.264,
P<0.05) and poorer self-esteem (r=0.382,
P=0.001), but not depression (r=0.189, P>0.05).
The relationship between insight and self-esteem remained significant after
controlling for depression (r=0.342, P<0.005), as did
that between insight and IQ (r=0.31, P=0.01). IQ and
self-esteem were not related (r=0.12, P=0.3).
In the regression analysis, the linear Insight Scale component was significant (R2 change 0.070, F change (1,65) 4.86, P<0.05), reflecting an association between higher Insight Scale score and higher IQ. The quadratic Insight Scale component was also highly significant (R2 change 0.127, F change (1,64) 10.11, P<0.005). The full model accounted for 19.6% of the variance, with an adjusted R2 of 0.17 (F (2,65) = 7.82, P<0.001). The quadratic Insight Scale component of the model remained significant when positive, negative and general PANSS sub-scale scores, as well as BDI scores, were entered into the model at the first step (R2 change 0.163, F change (1,60) 14.63, P<0.001). There was one IQ outlier more than 1.5 times the interquartile range above the upper quartile, and no Insight Scale outliers. When the analysis was run again excluding this outlier, the quadratic component of the regression remained significant.
Separate regressions for the three dimensions of the Insight Scale indicated that it was the `awareness of illness' dimension which was driving the curvilinear relationship between total Insight Scale score and IQ (Fig. 1), as this was the only dimension for which the quadratic component was significant (R2 change 0.181, F change (1,64) 7.763, P<0.005). Better insight in all three dimensions was significantly associated with poorer self-esteem (P<0.015 for all), but there were no significant correlations with depression.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMETHODRESULTSDISCUSSIONACKNOWLEDGMENTSREFERENCES |
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It has previously been suggested that the association between insight and IQ reflects the inability of people with low IQs to communicate the presence of insight to the satisfaction of an interviewer (Lewis, 1934; Rossell et al, 2003). This hypothesis is not supported by the present study, which did not find an association between observer-rated insight and IQ.
However, the linear association between total Insight Scale score and IQ is consistent with the findings of a number of previous studies (for a review see Cooke et al, 2005), as well as a recent study which utilised the Insight Scale (Donohoe et al, 2005). The significant curvilinear relationship between total Insight Scale score and IQ also supports the hypothesis of Green et al (2000) that there may be two influences on insight. First, high cognitive ability is conducive to, but in itself not sufficient for, having good insight. Second, some individuals may cope with psychosis in a way that promotes their own positive self-evaluation and thus manifest poor insight. The association found in this study between higher Insight Scale scores and poorer self-esteem is consistent with this, and suggests a further psychological mechanism whereby self-esteem is increased at the expense of insight, which may apply to all individuals across the IQ range. The combination of these two factors might explain why some people with high cognitive ability display good insight and others display poor insight, particularly in the `awareness of illness' dimension.
In the only previous study to find a curvilinear relationship between insight and cognitive ability, Startup (1996) found that a composite `cognitive deficits' score derived from factor analysis of neuropsychological test scores explained 56% of the variance in insight. No linear relationship with cognitive ability was found. Although we employed similar statistical methods to Startup (1996), our use of a single cognitive measure and a different insight scale might explain why the amount of variance accounted for by the regression model in this study was modest (20%), and why a linear as well as a curvilinear relationship, was found. Furthermore, although the Quick Test has been used in a number of studies of people with psychosis (e.g. Kondel et al, 2003), some evidence (Mortimer & Bowen, 1999) suggests that it overestimates IQ in this population. This may have influenced the results, particularly the high IQ outliers. Nevertheless, these data support the curvilinear relationship between cognitive ability and insight in a sample of out-patients with psychosis and complement the results from a sample of in-patients investigated by Startup (1996). The findings support the view that the relationship between insight and cognition may be complex, and may reflect an interaction between cognitive abilities and other factors, such as the way a person copes with psychosis. Poor insight, especially in people with good intellectual function, may be adaptive and serve to protect against low self-esteem.
Implications
Self-report measures of insight may be more sensitive to associations with
variables relevant to the aetiology of insight than single items from general
symptom rating scales. Different dimensions of insight may have different
psychological and cognitive correlates.
The finding that better insight is associated with poorer self-esteem, but not greater depression, suggests that insight might be more strongly related to stable, core beliefs about self-worth in people with psychosis than their current level of depressive symptomatology, which may be a result of a number of other factors, such as current social situation. If a person believes that they are mentally well despite disagreements with clinicians (`poor insight'), this might help to maintain positive core beliefs about the self and promote good self-esteem. Therefore poor insight could be viewed as an adaptive response to a diagnosis of a serious mental illness with respect to psychological well-being, although it can have maladaptive effects on other areas of functioning, such as engagement with services and taking medication.
Limitations
There are limitations to the generalisability of this study's sample, since
it was composed of out-patients who were recruited to a trial of
cognitive–behavioural therapy for psychosis. Although the mean level of
insight was comparable with samples reported in other studies using the
Insight Scale (Birchwood et al,
1994; Donohoe et al,
2005), our participants might not have been representative in
other ways, such as being more engaged with services, more motivated and less
cognitively impaired. Detailed information on the psychiatric diagnosis was
not available. Moreover, the curvilinear relationship between self-reported
insight and cognitive ability was modest and requires replication.
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ACKNOWLEDGMENTS |
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TOPABSTRACTINTRODUCTIONMETHODRESULTSDISCUSSIONACKNOWLEDGMENTSREFERENCES |
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REFERENCES |
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Ammons, R. B. & Ammons, C. H. (1962) The Quick Test. Psychological Test Specialists.
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Birchwood, M., Smith, J., Drury, V., et al (1994) A self-report Insight Scale for psychosis: reliability, validity and sensitivity to change. Acta Psychiatrica Scandinavica, 89, 62 -67.[Medline]
Cooke, M. A., Peters, E. R., Kuipers, E., et al (2005) Disease, deficit or denial? Models of poor insight in psychosis. Acta Psychiatrica Scandinavica, 112, 4-17.[CrossRef][Medline]
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Green, M. F., Kern, R. S., Robertson, M. J., et al (2000) Relevance of neurocognitive deficits for functional outcome in schizophrenia. In Cognition in Schizophrenia (eds T. Sharma & P. D. Harvey), pp. 178 -192. Oxford University Press.
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Rosenberg, M. (1965) Society and the Adolescent Self-Image. Princeton University Press.
Rossell, S. L., Coakes, J., Shapleske, J., et al (2003) Insight: its relationship with cognitive function, brain volume and symptoms in schizophrenia. Psychological Medicine, 33, 111 -119.[CrossRef][Medline]
Startup, M. (1996) Insight and cognitive deficits in schizophrenia: evidence for a curvilinear relationship. Psychological Medicine, 26, 1277 -1281.[Medline]
Received for publication March 23, 2006. Revision received April 20, 2007. Accepted for publication April 30, 2007.
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| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
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