Verbal learning contributes to cognitive insight in schizophrenia independently of affective and psychotic symptoms

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Abstract

Objective

Patients with schizophrenia exhibit distorted beliefs and experiences, and their own evaluation of this is labeled cognitive insight. We examined the relationship between cognitive insight and neurocognition, as well as the contribution of neurocognition in explaining cognitive insight.

Method

Clinically characterized patients with schizophrenia (n = 102) were assessed with a measure of cognitive insight, Beck Cognitive Insight Scale (BCIS) and a neuropsychological test battery. The contribution of neurocognition to the explained variance in BCIS components self-reflectiveness (i.e. objectivity and reflectiveness) and self-certainty (i.e. overconfidence in own beliefs) was examined controlling for current affective and psychotic symptoms.

Results

A significant negative correlation was found between self-certainty and verbal learning, whereas no associations were found between self-reflectiveness and any of the neuropsychological tests. Verbal learning was added significantly to the explained variance in self-certainty after controlling for potential confounders.

Conclusion

High self-certainty was associated with poor verbal learning. This suggests that overconfidence in own beliefs is associated with cognitive dysfunction in schizophrenia.

Research highlights

► There seems to be a moderate association between cognitive insight and cognition. ► Poor cognitive insight seems to be associated with poor verbal learning. ► High cognitive insight does not seem to be associated with neurocognition.

Introduction

Insight of illness encompasses the patient's awareness of symptoms as abnormal, attributing symptoms as well as social consequences to a mental disorder and recognizing the need for treatment (Amador et al., 1993, David, 1990). The clinical concept of insight is considered multidimensional (David, 1990) and distributed on a continuum (Markova & Berrios, 1992). A number of scales have been developed to assess insight of illness. The operationalized insight of illness has been valuable for determining the presence of mental illness and its prognosis, as well as prescribing appropriate treatment and management (Mintz et al., 2003), but does not essentially address the patient's capacity to evaluate own psychotic symptoms. Patients with psychosis might not only suffer from distorted beliefs and experiences, but are also relatively unable to reflect on them rationally and use corrective feedback (Beck et al., 2004). Their capacity and willingness to observe their mental productions and to consider alternative explanations and their confidence in own beliefs have been designated as cognitive insight (Beck et al., 2004). Cognitive insight can be measured with a reliable self-report, the Beck Cognitive Insight Scale. It has two components, self-reflectiveness measuring objectivity and reflectiveness and openness to feedback and self-certainty measuring mental flexibility or overconfidence in own beliefs. Weak to moderate associations have been found between these two subscales and both Birchwood's measure of insight (Beck et al., 2004, Pedrelli et al., 2004) and the PANSS insight item in schizophrenia (Engh et al., 2007), indicating that cognitive and clinical insights represent different domains.

Neurocognitive dysfunction is a key characteristic of schizophrenia (Heinrichs and Zakzanis, 1998, Keefe et al., 2006). To our knowledge there are only two reports on the relationship between neurocognition and cognitive insight. In the first study, a significant relationship between self-certainty and verbal learning and memory was found in 51 patients with first episode psychosis (Lepage et al., 2008). After a modest enlargement of the patient sample the strength of this relationship was somewhat attenuated, whereas the relationship between self-reflectiveness and verbal learning and memory was strengthened (Buchy et al., 2009). In a recent study significant relationships were found between self-certainty and visual and verbal memory, and also between self-certainty and scores on (modified) Wisconsin Card Sorting Test (Orfei et al., 2010). However, these studies did not control for potential confounders other than positive symptoms (PANSS positive subscale in the Buchy-study). In the present study we investigated the relationship between cognitive insight and neurocognition in a larger sample of patients with schizophrenia taking several potential confounders into account. There is a body of literature on the relationship between neurocognition and positive symptoms in schizophrenia, and a recent review showed no reliable association between the two (Dominguez et al., 2009). Few studies have, however, examined the specific relationships between neurocognition and delusions and hallucinations. Investigating the relationship between each of these positive symptoms and cognitive insight the occurrence of delusions seems to be associated with low self-reflectiveness and high self-certainty in schizophrenia (Engh et al., 2010). Hallucinations were not associated with either of the two cognitive insight dimensions (Engh et al., 2009). Yet, there are other potential confounders in the relationship between cognitive insight and neurocognition. One of these is depression. In a study investigating cognitive insight and depression, a significant positive relationship between self-reflectiveness and depression was found (Beck et al., 2004), but others did not report similar relationships (Pedrelli et al., 2004, Warman et al., 2007).

The relationship between illness duration and neurocognitive functioning in schizophrenia has been extensively studied. Empirical findings do not seem to support a steady cognitive decline with increasing chronicity (Gold et al., 1999, Heaton et al., 1994, Hyde et al., 1994, Mockler et al., 1997), but the role of chronic institutionalization is not clarified (Harvey et al., 1998, Harvey et al., 1999). To our knowledge no study has explored the relationship between cognitive insight and illness duration. We investigated whether illness duration could confound the relationship between cognitive insight and neurocognition.

Cognitive insight addressing the patient's own appraisal of pathological experiences and beliefs has an apparent conceptual overlap to neurocognition. Flexibility of thought and use of corrective feedback are essential to general intellectual abilities, and, thus, we anticipated a negative association between “overconfidence in own beliefs” and IQ. We examined the relationship between cognitive insight and neurocognition, as well as the contribution of neurocognition in explaining cognitive insight. Hence, the aim of the current study was to address the following questions: 1. Is there an association between self-certainty and neurocognition in schizophrenia? 2. Can neurocognition add to explained variance in self-certainty after contributions by potential confounders such as illness duration, insight of illness and affective and psychotic symptoms have been accounted for?

Section snippets

Participants

One hundred and two patients (schizophrenia, n = 81; schizophreniform disorder, n = 8; schizoaffective disorder, n = 13) participating in a large ongoing study on schizophrenia and bipolar disorders, the Thematic Organized Psychoses Research (TOP) Study, were included in the study. They were recruited from March 2005 through July 2007 in outpatient and inpatient psychiatric units at four University Hospitals in Oslo. These hospitals provide treatment for patients referred from primary care. The

Cognitive insight and neurocognitive test performance

The scores on self-reflectiveness, self-certainty and the neuropsychological subtests are shown in Table 3. The group performs within the lower-normal range compared to published norms. No significant correlations were found between self-reflectiveness and any of the neurocognitive subtests. Self-certainty showed a significant negative correlation with verbal learning (Table 4).

Explained variance in self-certainty

Verbal learning significantly added to explained variance in self-certainty after contributions by insight of illness,

Discussion

The main findings of the present study in schizophrenia was a significant negative relationship between self-certainty and verbal learning, indicating that the higher the verbal learning score, the better the cognitive insight as measured by reduced self-certainty. Verbal learning significantly added to the explained variance in self-certainty after contributions by insight of illness, depression and delusions had been taken into account. We found no association between self-reflectiveness and

Conclusion

We found that high self-certainty – a dimension of cognitive insight measuring overconfidence in own beliefs – is associated with poor verbal learning in schizophrenia. Verbal learning seems to make a unique contribution in explaining the variability in self-certainty, also when taking potential confounders such as depression and positive symptoms into account.

Conflict of interest

The authors declare that they have no conflicts of interests.

Acknowledgements

The investigators would like to thank the patients participating in the studies, and the members of the TOP study group who participated in data collection and data management. This research was supported by the Eastern Norway Health Authority (115–2005, 123–2004); Research Council of Norway, STORFORSK (167153); TOP study group; Free Research Funding Ulleval University Hospital; and Josef and Halldis Andresens legat. These institutions of funding had no further role in the study design, in the

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