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Christos Pantelis

Publications and source records attributed to Christos Pantelis.

At least 37 records · Page 2Linked to original sources
PubMed2005

The FOCIS international survey on psychiatrists' opinions on cognition in schizophrenia.

BACKGROUND: The goal of this project was to develop an interview to evaluate psychiatrists' views on the nature of cognitive dysfunction in schizophrenia, its importance as a potential treatment target, and its relative importance as a treatment target across different phases of schizophrenia. MATERIALS AND METHODS: A survey (available in paper or on-line) consisting of 27 questions, was developed by the Focus on Cognition in Schizophrenia (FOCIS) group, and distributed in a single wave mailing to 63,295 psychiatrists in 21 countries worldwide. RESULTS: The overall response rate was 4.7% (n=2975). The surveyed psychiatrists perceived cognition as a high treatment priority in stabilized schizophrenia patients, but less so for first episode or acute schizophrenia patients. The potential of atypical antipsychotics to improve cognitive dysfunction in schizophrenia was identified by 81% of the respondent psychiatrists. CONCLUSIONS: Cognitive deficits in people with schizophrenia are seen by clinical psychiatrists as relevant to treatment and rehabilitation plans. They were, however, regarded as a higher treatment priority in stabilized chronic rather than in first episode patients. The results suggest clinical psychiatrists need additional education regarding the nature of cognitive dysfunction in schizophrenia and its importance for psychosocial rehabilitation and community re-entry.

Attitude of Health Personnel↗
PubMed2005

A manual and automated MRI study of anterior cingulate and orbito-frontal cortices, and caudate nucleus in obsessive-compulsive disorder: comparison with healthy controls and patients with schizophrenia.

Functional imaging and neuropsychological data suggest that interconnected brain structures including the orbito-frontal cortex (OFC), anterior cingulate cortex (ACC) and caudate nucleus (CN) are involved in the pathophysiology of obsessive-compulsive disorder (OCD), but structural imaging studies investigating these regions have yielded inconclusive results. This may be due to inconsistencies in the identification of anatomical boundaries and methodologies utilised (i.e. automated vs. manual tracing). This magnetic resonance imaging study used manual tracing to measure volumes of selected brain regions (OFC, ACC and CN) in OCD patients and compared them with samples of healthy (HC) and psychiatric (schizophrenia; SCZ) controls (n=18 in each group). Concurrently, automated voxel-based analysis was also used to detect subtle differences in cerebral grey and white matter. For the OCD vs. HC comparison, there were no significant volumetric differences detected using the manual or the automated method (although the latter revealed a deficit in the subcortical white matter of the right temporal region). A direct comparison of the two patient groups showed no significant differences using the manual method. However, a moderate effect size was detected for OFC grey matter (reduced in SCZ), which was supported by findings of reduced OFC volume in the automated analysis. Automated analyses also showed reduced volumes in the dorsal (white matter) and ventral ACC (grey and white matter), as well as the left posterior cingulate (grey and white matter) in SCZ. The findings suggest that in contrast to findings in SCZ, there are very few (if any) gross structural anomalies in OCD.

Adult↗
PubMed2005

Functional connectivity during Stroop task performance.

Using covariance-based multivariate analysis, we examined patterns of functional connectivity in rCBF on a practice-extended version of the Stroop color-word paradigm. Color-word congruent and incongruent conditions were presented in six AB trials to healthy subjects during 12 H2(15)O PET scans. Analyses identified two reproducible canonical eigenimages (CE) from the PET data, which were converted to a standard Z score scale after cross-validation resampling and correction for random subject effects. The first CE corresponded to practice-dependent changes in covarying rCBF that occurred over early task repetitions and correlated with improved behavioral performance. This included many regions previously implicated by PET and fMRI studies of this task, which we suggest may represent two "parallel" networks: (i) a cingulo-frontal system that was initially engaged in selecting and mapping a task-relevant response (color naming) when the attentional demands of the task were greatest; and (ii) a ventral visual processing stream whose concurrent decrease in activity represented the task-irrelevant inhibition of word reading. The second CE corresponded to a consistent paradigmatic effect of Stroop interference on covarying rCBF. Coactivations were located in dorsal and ventral prefrontal regions as well as frontopolar cortex. This pattern supports existing evidence that prefrontal regions are involved in maintaining attentional control over conflicting response systems. Taken together, these findings may be more in line with theoretical models that emphasize a role for practice in the emergence of Stroop phenomena. These findings may also provide some additional insight into the nature of anterior cingulate- and prefrontal cortical contributions to implementing cognitive control in the brain.

Arousal↗
PubMed2005

Early processing deficits in object working memory in first-episode schizophreniform psychosis and established schizophrenia.

BACKGROUND: While there are many studies showing working-memory deficits in schizophrenia there are only a few that disentangle impairments for working-memory subprocesses such as perceptual, attentional, mnemonic and executive function. METHOD: In this study of delay-dependent memory, 55 patients with schizophreniform psychosis, 50 with established schizophrenia and 56 healthy controls were investigated. Using the delayed matching-to-sample task from the Cambridge Neuropsychological Test Automated Battery (CANTAB), performance deficits were found in both patient groups after controlling for age and pre-morbid IQ. RESULTS: Even after controlling for simultaneous matching-to-sample ability (i.e. perceptual matching), impaired performance in both patient groups was found as soon as the stimuli were no longer present. Impaired performance was not due to different types of errors in patients versus controls. Performance in both patient groups was comparable, except for a slight decrease of overall task performance. This suggests that the deficit is relatively stable during the course of the illness. CONCLUSIONS: Our results suggest a deficit in patients with psychotic illness in the initial processes necessary to actively maintain information, such as the ability to form an internal representation of complex objects.

Adolescent↗
PubMed2005

Increased pituitary volume in antipsychotic-free and antipsychotic-treated patients of the AEsop first-onset psychosis study.

Subjects at their first psychotic episode show an enlarged volume of the pituitary gland, but whether this is due to hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, or to stimulation of the prolactin-secreting cells by antipsychotic treatment, is unclear. We measured pituitary volume, using 1.5-mm, coronal, 1.5 T, high-resolution MRI images, in 78 patients at the first psychotic episode and 78 age- and gender-matched healthy controls. In all, 18 patients were antipsychotic-free (12 of these were antipsychotic-naïve), 26 were receiving atypical antipsychotics, and 33 were receiving typical antipsychotics. As hypothesized, patients had a larger pituitary volume than controls (+22%, p< 0.001). When divided by antipsychotic treatment, and compared to controls, the pituitary volume was 15% larger in antipsychotic-free patients (p=0.028), 17% larger in patients receiving atypicals (p=0.01), and 30% larger in patients receiving typicals (p<0.001). Patients receiving typicals not only had the largest pituitary volume compared to controls but also showed a trend for a larger pituitary volume compared to the other patients grouped together (+11%, p=0.08). When divided by diagnosis, and compared to controls, the pituitary volume was 24% larger in patients with schizophrenia/schizophreniform disorder (n=40, p<0.001), 19% larger in depressed patients (n=13, p=0.022), 16% larger in bipolar patients (n=16, p=0.037), and 12% larger in those with other psychoses (n=9, p=0.2). In conclusion, the first-episode of a psychotic disorder is associated with a larger pituitary independently of the presence of antipsychotic treatment, and this could be due to activation of the HPA axis. Typical antipsychotics exert an additional enlarging effect on pituitary volume, likely to be related to activation of prolactin-secreting cells. This activation of the hormonal stress response could participate to the important metabolic abnormalities observed in patients with psychosis.

Adolescent↗
PubMed2005

Diseases of white matter and schizophrenia-like psychosis.

OBJECTIVE: To analyse the available data regarding the presentation of psychosis in diseases of central nervous system (CNS) white matter. METHOD: The available neurological and psychiatric literature on developmental, neoplastic, infective, immunological and other white matter diseases was reviewed. RESULTS: A number of diseases of the white matter can present as schizophrenia-like psychoses, including leukodystrophies, neoplasms, velocardiofacial syndrome, callosal anomalies and inflammatory diseases. CONCLUSIONS: Production of psychotic symptoms may result from functional asynchrony of interdependent regions, due to alterations in critical circuits as a result of pathology. The nature, location and timing of white matter pathology seem to be the key factors in the development of psychosis, especially during the critical adolescent period of association area myelination. Diseases that disrupt the normal formation of myelin appear to cause psychosis at higher rates than those that disrupt mature myelinated structures. Diffuse rather than discrete lesions, in particular those affecting frontotemporal zones, are also more strongly associated with schizophrenia-like psychosis. These illnesses point to the central role that white matter plays in maintaining CNS connectivity and to how pathology of the white matter may contribute to the neurobiology of psychosis.

Brain Diseases↗
PubMed2005

Memory impairments identified in people at ultra-high risk for psychosis who later develop first-episode psychosis.

OBJECTIVE: While cognitive deficits are frequently reported in psychotic disorders, it is unclear whether these impairments predate the onset of illness and to what extent they are predictive of later transition to psychosis. METHOD: The authors studied 37 healthy volunteers and 98 symptomatic, help-seeking patients meeting the inclusion criteria of a treatment program for people at ultra-high risk for psychosis. Of the ultra-high-risk patients, 34 (34.7%) developed psychosis over the course of the investigation. Premorbid and current IQ, attention, memory, and executive functioning were measured with instruments including subtests from the Wechsler Memory Scale-Revised (WMS-R). Analyses compared the ultra-high-risk patients who became psychotic, those who did not become psychotic, and the comparison subjects. RESULTS: Overall, the ultra-high-risk subjects had significantly lower performance IQs than the comparison subjects. Further, impairments were also found in the visual reproduction subtest and the verbal memory index (predominantly owing to lower logical memory scores) of the WMS-R that were specific to the ultra-high-risk-patients who developed psychosis. No other memory, attentional, or executive tasks discriminated between any of the groups. CONCLUSIONS: These findings suggest that visuospatial processing impairment and some memory deficits were apparent before the full expression of psychotic illness. Cognitive performance on more complex tasks requiring rapid registration and efficient recall may be compromised before development of first-episode psychosis. Further experimental tasks that challenge these cognitive domains are required to clarify the predictive value of these results.

Adolescent↗
PubMed2005

Neurobiology of early psychosis.

BACKGROUND: Neurobiological studies of the early course of psychoses, such as schizophrenia, allow investigation of pathophysiology without the confounds of illness chronicity and treatment. AIMS: To review the recent literature on the biology of the early course of psychoses. METHOD: We carried out a critical appraisal of the recent findings in the neurobiology of early psychoses, using structural, functional and neurochemical imaging techniques. RESULTS: Brain structural alterations are present early in the illness and may predate symptom onset. Some changes, notably those in frontal and temporal lobes, can progress during the early phases of the illness. Functional and neurochemical brain abnormalities can also be seen in the premorbid and the early phases of the illness. Some, although not all, changes can be trait-like whereas some others might progress during the early years. CONCLUSIONS: A better understanding of such changes, especially during the critical periods of the prodrome, around the transition to the psychotic phase and during the early phases of the illness is crucial for continued research into preventive intervention strategies.

Brain↗
PubMed2004

Attenuation of perceptual asymmetries in patients with early-onset schizophrenia: evidence in favour of reduced hemispheric differentiation in schizophrenia?

Lateral biases in visual perception have been demonstrated in normal individuals and in patients with unilateral brain lesions. It has been suggested that the absence of structural and functional asymmetries in schizophrenia could be due to a failure in lateralisation that may be most pronounced in those patients whose illness onset is at an early age. Here we examined lateral biases in patients with schizophrenia of an early onset (N = 21) and a late onset (N = 19), and their respective age-matched control groups, using the greyscales task, a sensitive measure of asymmetries in visual processing. The stimuli consisted of two rectangles, one above the other, shaded in opposite directions and matched overall for darkness. Participants judged which of the two rectangles looked darker overall. Previous studies using this task in healthy participants have reported a reliable bias, such that the rectangle with the darker end on the left is selected preferentially. Whereas the late-onset patients in this study exhibited a perceptual bias of similar direction and magnitude to that of controls, this was not the case for the early-onset patients, who exhibited significantly less bias than their control group. The reduced perceptual bias seen in the early-onset group, but not the late-onset group, suggests an attenuation of right hemisphere mechanisms dedicated to processing visuospatial information. The attenuated perceptual asymmetry in the early-onset group only may be consistent with the view that (i) an earlier illness onset reflects a greater loss of hemispheric differentiation and (ii) reduced functional asymmetries in the early-onset group are a manifestation of a failure to allocate functions to one or the other hemisphere.

Adolescent↗
PubMed2004

Insight and hopelessness in forensic patients with schizophrenia.

OBJECTIVE: To quantitatively explore the level of insight in forensic patients with schizophrenia, and its relationship to symptoms and to a history of violence. In addition, to test the hypothesis that scores in the insight domains of 'compliance' and 'awareness of illness' are positively correlated with scores on a self-report scale measuring 'hopelessness'. METHOD: The study consisted of a cross-sectional survey. Subjects were inpatients and outpatients in the rehabilitation service of the Victorian Institute of Forensic Mental Health. Twenty-eight patients with a diagnosis of schizophrenia and a history of serious offending consented to take part. Twenty-two of these had committed homicide. Measures were obtained for each on the Schedule for Assessment of Insight, the Positive and Negative Syndrome Scale for Schizophrenia and the Beck Hopelessness Scale. RESULTS: The mean insight score for forensic patients was 8.39 (SD 4.88). Insight scores did not differ significantly between those subjects who had a history of violence prior to their index offence and those who did not. Awareness of illness, but not compliance, was positively correlated with level of hopelessness. A higher level of awareness of having a mental illness was thus related to feeling more hopeless about the future. CONCLUSIONS: Mean insight scores in patients with schizophrenia with a forensic history do not differ significantly from those in non-forensic populations. Being more aware of being mentally ill may be a risk factor for hopelessness about the future. The limitations of the study are the small sample size, and the fact that it is confined to a relatively clinically stable population.

Adult↗
PubMed2004

Individual differences in anterior cingulate/paracingulate morphology are related to executive functions in healthy males.

The neuropsychological correlates of inter-individual variations in cortical folding are poorly understood. Anterior cingulate (AC) cortex is one region characterized by considerable variability, particularly with respect to the paracingulate sulcus (PCS), which is present in only 30-60% of individuals and more commonly found in the left cerebral hemisphere. To investigate whether inter-individual differences in this PCS asymmetry are related to cognitive performance, we classified 30 healthy right-handed males as displaying either a leftward, rightward or symmetric pattern of folding based on the incidence and extent of the PCS in each hemisphere, and compared their performance on tasks engaging executive cognitive processes associated with frontal lobe function. We found that the more common leftward PCS asymmetry was associated with better performance across verbal and non-verbal executive tasks, but that PCS variability had no effect on tasks less dependent on executive functions. These results suggest that the leftward pattern of folding is associated with a non-specific performance advantage on cognitively demanding executive function tasks, possibly due to differences in functional interactions between AC/paracingulate cortex and connected frontal regions. It therefore appears that normal variations in brain morphology are associated with individual differences in cognitive abilities.

Adult↗
PubMed2004

Addiction, a condition of compulsive behaviour? Neuroimaging and neuropsychological evidence of inhibitory dysregulation.

AIMS: Addiction has been conceptualized as a shift from controlled experimentation to uncontrolled, compulsive patterns of use. Current neurobiological models of addiction emphasize changes within the brain's reward system, such that drugs of abuse 'hijack' this system and bias behaviour towards further drug use. While this model explains the involuntary nature of craving and the motivational drive to continue drug use, it does not explain fully why some addicted individuals are unable to control their drug use when faced with potentially disastrous consequences. In this review, we argue that such maladaptive and uncontrolled behaviour is underpinned by a failure of the brain's inhibitory control mechanisms. DESIGN: Relevant neuroimaging, neuropsychological and clinical studies are reviewed, along with data from our own research. FINDINGS: The current literature suggests that in addition to the brain's reward system, two frontal cortical regions (anterior cingulate and orbitofrontal cortices), critical in inhibitory control over reward-related behaviour, are dysfunctional in addicted individuals. These same regions have been implicated in other compulsive conditions characterized by deficits in inhibitory control over maladaptive behaviours, such as obsessive-compulsive disorder. CONCLUSIONS: We propose that in chronically addicted individuals, maladaptive behaviours and high relapse rates may be better conceptualized as being 'compulsive' in nature as a result of dysfunction within inhibitory brain circuitry, particularly during symptomatic states. This model may help to explain why some addicts lose control over their drug use, and engage in repetitive self-destructive patterns of drug-seeking and drug-taking that takes place at the expense of other important activities. This model may also have clinical utility, as it allows for the adoption of treatments effective in other disorders of inhibitory dysregulation.

Behavior, Addictive↗
PubMed2004

Pituitary volume in psychosis.

BACKGROUND: Patients with psychosis have activation of the hypothalamic-pituitary-adrenal (HPA) axis during the acute phase of the psychosis. Whether this has any morphological consequences for the pituitary gland is currently unknown. AIMS: To examine pituitary volume variation in people at different stages of psychotic disorder. METHOD: Pituitary volume was measured using 1.5 mm, coronal magnetic resonance images in 24 people with first-episode psychosis, 51 with established schizophrenia and 59 healthy controls. RESULTS: Compared with the control group, the people with first-episode psychosis had pituitary volumes that were 10% larger, whereas those with established schizophrenia had pituitary volumes that were 17% smaller. In both of the groups with psychosis, there was no difference in pituitary volume between those receiving typical antipsychotic drugs and those receiving atypical antipsychotics. CONCLUSIONS: The first episode of a psychosis is associated with a larger pituitary volume, which we suggest is due to activation of the HPA axis. The smaller pituitary volume in the group with established schizophrenia could be the consequence of repeated episodes of HPA axis hyperactivity.

Acute Disease↗
PubMed2004

Efficacy and tolerability of ziprasidone versus risperidone in patients with acute exacerbation of schizophrenia or schizoaffective disorder: an 8-week, double-blind, multicenter trial.

BACKGROUND: More head-to-head comparisons of antipsychotics are needed to discern the relative efficacy and safety profiles of these compounds. Thus, we compared ziprasidone and risperidone in patients with acute exacerbation of schizophrenia or schizoaffective disorder. METHOD: Patients with DSM-III-R acute exacerbation of schizophrenia or schizoaffective disorder were randomly assigned to double-blind ziprasidone 40 to 80 mg b.i.d. (N = 149) or risperidone 3 to 5 mg b.i.d (N = 147) for 8 weeks. Primary efficacy measures included Positive and Negative Syndrome Scale (PANSS) total score and Clinical Global Impressions-Severity of Illness scale (CGI-S) score; secondary measures included scores on the PANSS negative sub-scale, CGI-Improvement scale (CGI-I), and PANSS-derived Brief Psychiatric Rating Scale (BPRSd) total and core items. Safety assessments included movement disorder evaluations, laboratory tests, electrocardiography, vital signs, and body weight. Efficacy analyses employed a prospectively defined Evaluable Patients cohort. Treatment equivalence was conferred if the lower limit of the 95% confidence interval of the ziprasidone/risperidone ratio of least-squares mean change from baseline was > 0.60. Data were gathered from August 1995 to January 1997. RESULTS: Equivalence was demonstrated in PANSS total scores, CGI-S scores, PANSS negative subscale scores, BPRSd total and core item scores, and PANSS total and CGI-I responder rates. Both agents were well tolerated. Risperidone exhibited a significantly higher Movement Disorder Burden (MDB) score (p < .05) and higher incidences of prolactin elevation and clinically relevant weight gain. However, compared with current recommendations, study dosing may have been high for some risperidone-treated patients (mean dose = 7.4 mg/day) and low for some ziprasidone-treated patients (mean dose = 114.2 mg/day). CONCLUSION: Both agents equally improved psychotic symptoms, and both were generally well tolerated, with ziprasidone demonstrating a lower MDB score and less effect on prolactin and weight than risperidone.

Adult↗
PubMed2003

Managing patients with "treatment-resistant" schizophrenia.

Patients who fail to respond adequately to pharmacological treatment present an ongoing therapeutic challenge. The term "incomplete recovery" (IR) is preferred to the current term "treatment resistance" to describe these patients. IR should be considered from a multidimensional perspective that includes a broad range of symptoms and functional disabilities that are relevant to schizophrenia. The approach to the incompletely recovered patient needs to be systematic, with consideration given to the factors that may hamper recovery. "Atypical" (second-generation) antipsychotic drugs target various domains of symptoms relevant to IR. Adjunctive treatment strategies (eg, mood stabilisers, antidepressants, combinations of antipsychotics) may be useful, but should be undertaken in specialist psychiatric settings. Although pharmacological treatment is a necessary first step in managing incompletely recovered patients, adjunctive psychosocial interventions are needed to optimise treatment success.

Antidepressive Agents↗
PubMed2003

Medical comorbidity in schizophrenia.

Schizophrenia has been described as a "life-shortening disease", and physical comorbidity accounts for 60% of premature deaths not related to suicide. People with schizophrenia and other mental illnesses have a higher rate of preventable risk factors such as smoking, high alcohol consumption, poor diet, and lack of exercise. Recognition and management of morbidity in people with mental illness are made more difficult by barriers related to the patient, the illness, the attitudes of medical practitioners, and the structure of healthcare delivery services. Improved detection and treatment of medical illness in people with schizophrenia will have significant benefits for their psychosocial functioning and overall quality of life.

Alcoholism↗
PubMed2003

Neuroanatomical abnormalities before and after onset of psychosis: a cross-sectional and longitudinal MRI comparison.

BACKGROUND: Psychotic disorders, such as schizophrenia, are associated with neuroanatomical abnormalities, but whether these predate the onset of symptoms or develop progressively over the course of illness is unclear. We investigated this issue with MRI to study people with prodromal symptoms who are at ultra high-risk for the development of psychosis. METHODS: We did two comparisons, cross-sectional and longitudinal. For the cross-sectional comparison, 75 people with prodromal signs of psychosis were scanned with MRI. After at least 12 months of follow-up, 23 (31%) had developed psychosis and 52 (69%) had not. Baseline MRI data from these two subgroups were compared. For the longitudinal comparison, 21 of the ultra high-risk individuals were scanned again with MRI after at least 12 months. Ten of these had developed psychosis and 11 had not. MRI data from baseline and follow-up were compared within each group of people. FINDINGS: In the cross-sectional comparison, compared with people who did not develop psychosis, those who did develop the disorder had less grey matter in the right medial temporal, lateral temporal, and inferior frontal cortex, and in the cingulate cortex bilaterally. In the longitudinal comparison, when re-scanned, individuals who had developed psychosis showed a reduction in grey matter in the left parahippocampal, fusiform, orbitofrontal and cerebellar cortices, and the cingulate gyri. In those who had not become psychotic, longitudinal changes were restricted to the cerebellum. INTERPRETATION: Some of the grey-matter abnormalities associated with psychotic disorders predate the onset of frank symptoms, whereas others appear in association with their first expression.

Adult↗