Increased plasma levels of thioredoxin-1 in patients with first episode psychosis and long-term schizophrenia

Excessive level of radicals and/or dysfunctional antioxidant response, oxidative stress, is implicated in the pathogenesis of schizophrenia. A condition of oxidative stress has been detected in the brain, peripheral tissues and fluids including plasma. Plasma thioredoxin-1 (Trx1) is well characterized and a putative marker for oxidative stress and recently shown to be increased in plasma at the onset of schizophrenia.The present study aimed to explore whether Trx1 can be used as a marker to identify schizophrenic patients at the time-point when patients have their first episode of psychosis as compared to patients with long-term schizophrenia and mentally healthy patients, respectively.Plasma samples obtained from 18 patients at first episode of psychosis, from 49 long-term schizophrenic patients and from 20 mentally healthy controls (admitted with minor physical injury to the general ward) where analyzed by ELISA for Trx1. The patients with first episode of psychosis were diagnosed at least 6 months later and shown to constitute various psychotic syndromes, including schizophrenia, or affective disorder.The concentration of Trx1 in the patients with first episode of psychosis was 1.5 ± 1.0 ng/ml and 0.8 ± 0.6 ng/ml in controls. In the long-term schizophrenic patients the plasma concentration was 1.5 ± 0.7. The differences between the groups of acute psychotic or long-term schizophrenia patients to controls were significant (p < 0.016 and p < 0.001, respectively).Our data indicate that Trx1 may not be used as an early marker to identify schizophrenic patients in a mixed population of first episode psychotic patients. Further, Trx1 did not discriminate with reliable accuracy patients with psychotic disorder from mentally healthy controls on an individual basis due to overlap in levels of Trx1. However, our observations show that psychotic patients in general are in a significant long-term condition of oxidative stress, with possible implications for the profound morbidity and mortality found in this patient population.     

Oxidative-antioxidative systems and their relation with serum S100 B levels in patients with schizophrenia: effects of short term antipsychotic treatment

Oxidative stress may be a contributing factor in the etiopathophysiology of schizophrenia, which may be exacerbated by the treatment with antipsychotics with pro-oxidant properties. Increased levels of S100 B are associated with neurodegenerative disorders, including schizophrenia. The aim of the present study was to investigate the role of oxidative cell damage in the pathogenesis of schizophrenia. Forty patients who fully met the fourth Diagnostic and Statistical Manual of Mental Disorders criteria for schizophrenia and 35 healthy control subjects were included in the study. Serum S100 B level was determined to investigate brain damage. Plasma malondialdehyde (MDA) levels and susceptibility of red blood cell (RBC) to oxidation were determined to investigate the oxidative status and plasma vitamin E, vitamin C, serum total carotenoid levels and total antioxidant capacity and RBC superoxide dismutase (SOD) and whole blood glutathione peroxidase activities were measured to investigate the antioxidative defence before and after 6 weeks of antipsychotic treatment. Plasma MDA and serum S100 B levels and RBC-SOD activity were significantly higher in the schizophrenia group than those of the control group. Treatment did not modify any of the oxidative-antioxidative system parameters or serum S100 B levels. S100 B level was significantly higher in patients with negative symptoms than the patients with positive symptoms and the control subjects. S100 B levels were significantly reduced after 6 weeks of treatment in patients with negative symptoms. The results of the present study might support the oxidative cell injury hypothesis of the schizophrenia. Furthermore, the underlying mechanisms of the subgroups of schizophrenia might be different as suggested by the increased S100 B levels and its decrement after treatment in patients with negative symptoms.     

Elevated plasma superoxide dismutase in first-episode and drug naive patients with schizophrenia: inverse association with positive symptoms

Excessive free radical production or oxidative stress may be involved in the pathophysiology of schizophrenia as evidenced by increased superoxide dismutase (SOD) activities, a critical enzyme in the detoxification of superoxide radicals. This study compared plasma SOD activities in 78 never-medicated first-episode and 100 medicated chronic schizophrenia patients to 100 healthy control subjects and correlated these SOD activities with the Positive and Negative Syndrome Scale (PANSS) among the schizophrenic patients. We found that both first-episode and chronic patients had significantly increased plasma SOD activities compared to controls, and that chronic schizophrenic patients on antipsychotic medication had significantly higher SOD activities than first episode schizophrenic patients. Plasma SOD activities were also negatively correlated with positive symptoms of schizophrenia, but only in first-episode patients. Thus, oxidative stress appears to be greater in first episode schizophrenic patients with fewer positive symptoms and may become greater as schizophrenia becomes more chronic, although we cannot exclude the possibility that chronic antipsychotic treatment may increase SOD activities and presumed oxidative stress in schizophrenia.     

Longitudinal volume changes of the pituitary gland in patients with schizotypal disorder and first-episode schizophrenia

An enlarged volume of the pituitary gland has been reported in the schizophrenia spectrum, possibly reflecting the hypothalamic-pituitary-adrenal (HPA) hyperactivity. However, it remains largely unknown whether the pituitary size longitudinally changes in the course of the spectrum disorders. In the present study, longitudinal magnetic resonance imaging (MRI) data were obtained from 18 patients with first-episode schizophrenia, 13 patients with schizotypal disorder, and 20 healthy controls. The pituitary volume was measured at baseline and follow-up (mean, 2.7 years) scans and was compared across groups. The pituitary volume was larger in the schizophrenia patients than controls at baseline, and both patient groups had significantly larger pituitary volume than controls at follow-up. In a longitudinal comparison, both schizophrenia (3.6%/year) and schizotypal (2.7%/year) patients showed significant pituitary enlargement compared with controls (− 1.8%/year). In the schizophrenia patients, greater pituitary enlargement over time was associated with less improvement of delusions and higher scores for thought disorders at the follow-up. These findings suggest that the pituitary gland exhibits ongoing volume changes during the early course of the schizophrenia spectrum as a possible marker of state-related impairments.     

The novel oxidative stress marker thioredoxin is increased in first-episode schizophrenic patients

Excessive free radical production leading to oxidative stress may be involved in the pathophysiology of schizophrenia. Oxidative stress increases serum thioredoxin (TRX), a redox-regulating protein with antioxidant activity recognized as an oxidative-stress marker. The aim of this study was to assess the clinical significance of serum TRX levels in various stages of schizophrenia. Serum TRX levels were determined using ELISA from 60 never-medicated first-episode and 66 medicated chronic schizophrenia patients and 66 healthy control subjects matched for age and gender. The psychopathology of schizophrenia was assessed by the Positive and Negative Syndrome Scale (PANSS). Our results showed that group comparison between first-episode and chronic patients and control groups revealed significantly increased serum TRX only in first-episode patients. Increased levels of TRX in patients experiencing an acute stage schizophrenic episode was also significantly higher compared to chronic schizophrenic patients on antipsychotic medication. Serum TRX was also positively correlated with positive symptoms of schizophrenia. Our results suggest oxidative stress occurs in an acute stage of schizophrenic episode and may have an important role in pathogenesis and symptomology of schizophrenia. Lower TRX levels in chronic patients treated with antipsychotics may have implications for treatment outcome.     

A follow-up MRI study of the fusiform gyrus and middle and inferior temporal gyri in schizophrenia spectrum

While longitudinal magnetic resonance imaging (MRI) studies have demonstrated progressive gray matter reduction of the superior temporal gyrus (STG) during the early phases of schizophrenia, it remains largely unknown whether other temporal lobe structures also exhibit similar progressive changes and whether these changes, if present, are specific to schizophrenia among the spectrum disorders. In this longitudinal MRI study, the gray matter volumes of the fusiform, middle temporal, and inferior temporal gyri were measured at baseline and follow-up scans (mean inter-scan interval = 2.7 years) in 18 patients with first-episode schizophrenia, 13 patients with schizotypal disorder, and 20 healthy controls. Both schizophrenia and schizotypal patients had a smaller fusiform gyrus than controls bilaterally at both time points, whereas no group difference was found in the middle and inferior temporal gyri. In the longitudinal comparison, the schizophrenia patients showed significant fusiform gyrus reduction (left, − 2.6%/year; right, − 2.3%/year) compared with schizotypal patients (left: − 0.4%/year; right: − 0.2%/year) and controls (left: 0.1%/year; right: 0.0%/year). However, the middle and inferior temporal gyri did not exhibit significant progressive gray matter change in all diagnostic groups. In the schizophrenia patients, a higher cumulative dose of antipsychotics during follow-up was significantly correlated with less severe gray matter reduction in the left fusiform gyrus. The annual gray matter loss of the fusiform gyrus did not correlate with that of the STG previously reported in the same subjects. Our findings suggest regional specificity of the progressive gray matter reduction in the temporal lobe structures, which might be specific to overt schizophrenia within the schizophrenia spectrum.     

Maintenance electroconvulsive therapy (ECT) for treatment-resistant disorganized schizophrenia

Patients who have not responded to recommended antipsychotic medications should be considered for electroconvulsive therapy (ECT). However, there has been controversy about the standardized methods of continuation and maintenance ECT in the management of treatment-resistant schizophrenia. We describe a patient with a serious case of disorganized schizophrenia who had not responded well with any typical and atypical antipsychotic drug for seven years, but responded remarkably to acute ECT. Continuation ECT was necessary to sustain a positive therapeutic response. The patient showed dramatic improvement from 70 to 20 in the 18-item Brief Psychiatric Rating Scale (BPRS) score (71% reduction) after acute ECT and continuation ECT. Using maintenance ECT, she was able to live in the custody of her parents after 7-years hospitalization. This case report suggests that continuation and maintenance ECT benefits patients with serious cases of refractory schizophrenia.     

Vascular Endothelial Growth Factor (VEGF) serum concentration during electroconvulsive therapy (ECT) in treatment resistant depressed patients

Vascular endothelial growth factor (VEGF) is an angiogenic cytokine, which induces vasopermeability and facilitates neurogenesis and synaptic plasticity in the adult brain. Expression studies in animal models have reported that brain VEGF is regulated by electroconvulsive seizures (ECS), which are used in an experimental paradigm similar to clinical electroconvulsive therapy (ECT) a treatment for drug resistant depressed (TRD) patients. The aim of this study was to investigate putative modulations of ECT on VEGF serum levels in TRD patients.Nineteen patients were enrolled in the study; illness severity and VEGF serum contents were assessed before the treatment (T0), the day after the end of ECT (T1) and one month later the end of ECT (T2).ECT treatment improved depression symptomatology as measured by MADRS scores (p < 0.0001). No changes occurred in serum VEGF between T0 and T1, whereas a significant increase was observed between T0 and T2 (p = 0.042). Moreover a significant correlation was observed between the VEGF increase at T2 and the reduction in MADRS scores (p = 0.049).This study is the first to evaluate putative modulations of serum VEGF induced by ECT in TRD patients.     

Serum Oxidative Stress Marker Levels in Unmedicated and Medicated Patients with Schizophrenia

Oxidative stress has been suggested to be involved in schizophrenia, but studies have demonstrated inconsistent results on oxidative stress marker level/activity in patients with schizophrenia. In order to clarify the circulating oxidative stress marker level/activity in patients with schizophrenia, this study recruited 80 schizophrenia patients (40 first-episode, drug-free and 40 chronically medicated patients) and 80 controls to analyze serum activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC), and levels of lipid peroxidation marker malondialdehyde (MDA) in schizophrenia patients, and whether they associate with the severity of the disease. We showed that only serum GSH-Px activity was significantly reduced in unmedicated patients with schizophrenia when compared with control subjects, whereas the other three analyzed oxidative stress markers did not show significant differences between cases and controls. Moreover, our results demonstrated that chronic medication increased GSH-Px activity and MDA levels in patients with schizophrenia, but reduced SOD activity in the patients. We also found that short-term antipsychotic treatments on the patients with schizophrenia reduced the SOD activity. Correlation analyses indicated that the oxidative stress marker activity/level is not significantly associated with the severity of schizophrenia, except that SOD level correlated with PANSS positive score significantly. Taken together, the data from the present study suggested that the dysfunctions of oxidative stress markers in patients with schizophrenia were mainly caused by antipsychotics, emphasizing increased oxidative stress as a potential side effect of antipsychotics on the patients.     

Oxidative stress and neopterin abnormalities in schizophrenia: A longitudinal study

Oxidative stress abnormalities have been proposed to explain the pathogenesis of schizophrenia. The present study examined neopterin and oxidative stress abnormalities in schizophrenia patients before and after treatment. Serum neopterin, total anti-oxidants, nitrites and thiols in antipsychotic-naïve schizophrenia patients (n = 45) were assessed at baseline before treatment in comparison with healthy controls (n = 43). The schizophrenia patients on treatment were followed up for 3 months and these parameters were reassessed (n = 32). In comparison to healthy controls, schizophrenia patients had significantly higher levels of neopterin and nitrites and significantly lower levels of anti-oxidants before treatment. During follow-up assessments in schizophrenia patients after treatment with antipsychotics, there was a significant decrease in the neopterin levels and significant increase in anti-oxidant levels. Our study observations support increased oxidative stress in schizophrenia that improves with antipsychotic treatment.     

Reduced plasma total antioxidant status in first-episode drug-naive patients with schizophrenia

Excessive free radical production leading to oxidative stress may be involved in the pathophysiology of schizophrenia. Determination of total antioxidant status (TAS) provides an index of the sum of activities of all antioxidants. However, there have been few systematic studies to examine the relationship between TAS levels and psychopathology in first-episode and drug-naive patients with schizophrenia.TAS levels were determined in the plasma of 60 never-medicated first-episode patients with schizophrenia and 68 healthy control subjects. The schizophrenia symptomatology and the depressive symptoms were assessed by the positive and negative syndrome scale (PANSS) and the Hamilton rating scale for depression (HAMD). The results showed that TAS levels were significantly lower in first-episode patients with schizophrenia than in healthy control subjects (159.8 ± 45.8 U/ml vs 211.4 ± 46.8 U/ml, F = 39.5, df = 1, 126, p < 0.001). A trend toward significant inverse correlation between TAS levels and PANSS negative subscore was observed (r = 0.25, df = 60, p = 0.06). Our results suggest that oxidative stress occurs in an early course of schizophrenia and may have an important role in pathogenesis and perhaps, negative symptomatology of schizophrenia.     

Practice of electroconvulsive therapy at the research and training hospital in Turkey

Objective  We sought to obtain an overview of electroconvulsive therapy (ECT) practice in Bakirkoy Research and Training Hospital for Psychiatric and Neurological Diseases, which is the biggest hospital for psychiatry in Turkey. Method  From 1st January 2006 to 30th June 2007, a form enquiring about evaluation of ECT was filled retrospectively. Results  The total number of patients, admitted for psychiatry during the survey period was 265,283. A total of 1,531 patients (12.4% among inpatients and 0.58% in all psychiatric admissions) received 13,618 sessions (including multiple hospitalizations) of ECT from 12,341 psychiatric inpatients during the survey period. Ninety-eight patients had multiple hospitalizations. The male-to-female ratio was 1.26–1. Patients with bipolar affective disorder, current episode manic with or without psychotic symptoms received ECT most frequently (30.3%), followed by patients with schizophrenia (29.5%), severe depressive episode with or without psychotic symptoms (include bipolar affective disorder current episode severe depression) (15.2%), other non-organic psychotic disorders (14.4%), schizoaffective disorders (6.3%), mental and behavioral disorders due to psychoactive substance abuse with psychotic disorders (3.5%) and catatonic schizophrenia (0.7%). Patients who received ECT were in age group of 25–44 years (64.7%), followed by 45–64 years (17.7%), 18–24 years (15.4%), 65 years and older (1.4%), and younger than 18 years (0.8%). All patients received modified ECT. There were no ECT-related deaths during the survey. Conclusion  The rate of ECT among all psychiatric inpatients during the survey period was 12.4%. The majority of patients who received ECT were diagnosed with bipolar affective disorder-current episode manic and schizophrenia. ECT training programs for psychiatry residents and specialists should be planned, and conducted systematically.     

Reduced antioxidant defense systems in schizophrenia and bipolar I disorder

Numerous evidence and proofs suggest that the oxidative stress contributes to the pathogenesis of schizophrenia (SZ) and bipolar disorder (BD). The aim of this study is to determine the glutathione levels and the antioxidant enzyme activities in blood samples of patients suffering from SZ and patients with bipolar disorder in comparison with the healthy controlled subjects. It was a case-controlled study carried on upon three groups: forty-six SZ patients (41 men and 5 women, mean age = 33.2 ± 7 years), thirty BD patients (25 men and 5 women, mean age = 31.3 ± 8 years) and forty healthy controls (33 men and 7 women, mean age = 32.3 ± 7 years).     

自由基代谢与精神分裂症临床症状和药物治疗的关系

目的：探讨自由基代谢与精神分裂症临床症状和药物治疗的关系。方法：是否治疗的慢性精神分裂症患者各４０例分别评定定阳性和阴性症状量表（ＰＡＮＳＳ）,并测定膜脂质过氧化物丙二醛（ＭＤＡ）含量、铜／锌超氧化物歧化酶（Ｇｕ－ＺｎＳＯＤ）和谷胱苷肽过氧化物酶（ＧＳＨ－Ｐｘ）活性。结果：与健康对照组相比,未治疗组患者ＭＤＡ含量和ＧＳＨ－Ｐｘ活性显著增加,治疗组患者无显著改变;而两组患者ＳＯＤ活性显著降低;未治疗     

Decreased serum BDNF levels in chronic institutionalized schizophrenia on long-term treatment with typical and atypical antipsychotics

Accumulating evidence showed that brain-derived neurotrophic factor (BDNF) may be involved in the pathophysiology of schizophrenia. Decreased BDNF levels have been found in the serum of schizophrenic patients with mixed results. In the present study, we assessed serum BDNF levels in a large group of 364 schizophrenic patients (157 on clozapine, 89 on risperidone and 118 on typical antipsychotics), compared to 323 healthy control subjects matched for age and gender. The schizophrenia symptomatology was assessed by the Positive and Negative Syndrome Scale (PANSS), and serum BDNF levels were measured by sandwich ELISA. The results showed that BDNF levels were significantly lower in chronic patients with schizophrenia than in healthy control subjects (9.9 ± 2.0 ng/ml vs.11.9 ± 2.3 ng/ml, p < 0.0001). Lower BDNF levels were observed in patients treated with risperidone (9.3 ± 2.3 ng/ml) compared to those with clozapine (10.2 ± 2.0 ng/ml, p < 0.001) and typical antipsychotics (10.0 ± 2.1 ng/ml, p < 0.01). Furthermore, a stepwise multiple regression analysis identified types of antipsychotic drugs (beta = − 0.37, t = − 3.15, p = 0.001) and BDNF levels (beta = − 0.26, t = − 2.51, p = 0.014) as the influencing factor for the positive symptom subscore of PANSS. In addition, there was a sex difference in BDNF levels in patients with schizophrenia (9.7 ± 1.9 ng/ml for males vs.10.4 ± 2.1 ng/ml for female, p < 0.005), but not in normal controls. Our findings indicated decreased BDNF serum levels in chronic patients with schizophrenia, which may be related to clinical phenotypes, including gender, antipsychotic treatment and the severity of psychotic symptoms.     

Deficient inhibition of return in chronic but not first-episode patients with schizophrenia

Background

Inhibition of return (IOR) has been tested in patients with schizophrenia with contradictory results. Some studies indicated that patients with schizophrenia have normal levels of IOR; however, other studies reported delayed or blunted IOR. Inconsistency in findings might be due to differences across studies in relevant aspects associated with disease, such as heterogeneity of the disorder, different medications, onset and severity of the illness. The present study was to explore different patterns of IOR in antipsychotic medication free first-episode schizophrenia and chronic schizophrenia.

Methods

Forty two patients with first-episode schizophrenia, 44 patients with chronic schizophrenia, and 38 healthy controls were included in the study. All subjects went through a covert orienting of attention task with seven stimulus onset asynchrony (SOA) intervals (400 ms, 500 ms, 600 ms, 700 ms, 800 ms, 1200 ms and 1500 ms).

Results

Compared with healthy controls, the magnitude and onset of IOR in first-episode patients with schizophrenia were intact. However, in patients with chronic schizophrenia, there was an attenuated cuing effect especially at SOA 700 ms; in addition, there was a robust IOR until at SOAs 800 ms or above. Moreover, the illness duration and the number of psychotic episodes were significantly correlated with the validity effect at SOAs 400 ms and 600 ms.

Conclusion

Our study suggests that deficient IOR presents in chronic but not in first-episode patients with schizophrenia. IOR deficit in schizophrenia may begin during the course of illness and deteriorate over the course of illness. Our findings are consistent with the neurodegenerative model of schizophrenia.     

Increased uric acid levels in drug-naïve subjects with bipolar disorder during a first manic episode

Recent evidence suggests that purinergic system dysfunction may play a role in the pathophysiology and therapeutics of bipolar disorder (BPD). Uric acid is a key nitrogenous end product of purine metabolism. In addition to being a potential marker of treatment response, high levels of uric acid may represent a state marker during mania. In this study, we assessed the presence of purinergic dysfunction in 20 treatment-naïve first episode patients with BPD who were experiencing a manic episode. Patients were matched with 24 healthy controls. We found that acutely manic patients had significantly higher levels of plasma uric acid (4.85 ± 1.60 mg/dL) compared to healthy controls (2.96 ± 0.63 mg/dL, p < 0.001; F = 28.1). No association between uric acid levels with severity of manic symptoms was observed. These results support the role of purinergic system dysfunction in BPD early in the course of illness, and suggest that this phenomenon is not the result of chronicity or medication exposure. Overall, our findings suggest a novel mechanism in the pathophysiology of BPD.     

Does hypofrontality expand to global brain area in progression of schizophrenia?: A cross-sectional study between first-episode and chronic schizophrenia

Although to date there have been no conclusive pathophysiological findings in support of the degenerative theory of the etiology of schizophrenia, the results of neuroimaging studies have suggested that progressive changes in the brain do occur during the clinical course of schizophrenia. However, there has been no report on alterations in regional cerebral blood flow (rCBF) under resting condition, which was compared between the first-episode and the chronic patients of schizophrenia and healthy controls. Therefore, in this study, we applied three-dimensional stereotactic surface projection analysis of resting SPECT (3D-SSP SPECT) in patients with first-episode (n = 18) and chronic schizophrenia (n = 23) and age-/sex-matched healthy controls (n = 40). The rCBFs in the middle/inferior/medial frontal gyrus and the anterior cingulate gyrus were significantly decreased in both patient groups, relative to the respective controls (Z > 3.0, P < 0.001, uncorrected). The chronic group showed significant hypoperfused region in the left inferior parietal lobule and middle/inferior temporal gyrus. Furthermore, within-cases comparison between the first-episode and chronic schizophrenia, revealed that the significant hypoperfused regions in the chronic group, compared to the first-episode group, were not only the lateral and medial prefrontal cortex, but also the inferior parietal cortex, posterior part of the temporal lobe, and the cuneus. The present study suggested that the reduction in rCBF occurs in the posterior brain area in addition to the frontal lobe across all clinical stages of schizophrenia.     

Working memory and attention deficits in adolescent offspring of schizophrenia or bipolar patients: comparing vulnerability markers

Background

Working memory deficits abound in schizophrenia and attention deficits have been documented in schizophrenia and bipolar disorder. Adolescent offspring of patients may inherit vulnerabilities in brain circuits that subserve these cognitive domains. Here we assess impairments in offspring of schizophrenia (SCZ-Offspring) or bipolar (BP-Offspring) patients compared to controls (HC) with no family history of mood or psychotic disorders to the second degree.

Methods

Three groups (n = 100 subjects; range: 10-20 yrs) of HC, SCZ-Offspring and BP-Offspring gave informed consent. Working memory was assessed using a delayed spatial memory paradigm with two levels of delay (2 s & 12 s); sustained attention processing was assessed using the Continuous Performance Task—Identical Pairs version.

Results

SCZ-Offspring (but not BP-Offspring) showed impairments in working memory (relative to HC) at the longer memory delay indicating a unique deficit. Both groups showed reduced sensitivity during attention but only BP-Offspring significantly differed from controls.

Conclusions

These results suggest unique (working memory/dorsal frontal cortex) and potentially overlapping (attention/fronto-striatal cortex) vulnerability pathways in adolescent offspring of patients with schizophrenia and bipolar disorder. Working memory and attention assessments in these offspring may assist in the clinical characterization of the adolescents vulnerable to SCZ or BP.     

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

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.