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A study of N-acetyl-aspartate (NAA) can provide data of interest about cortical alterations in psychotic illnesses. Although a decreased NAA level in the cerebral cortex is a replicated finding in chronic schizophrenia, the data are less consistent for bipolar disease. On the other hand, it is likely that NAA values in schizophrenia may differ in men and women.
We used proton magnetic resonance spectroscopy (1H MRS) to examine NAA levels in the prefrontal cortex in two groups of male patients, one with schizophrenia (n = 11) and the other with bipolar disorder (n = 13) of similar duration, and compared them to a sample of healthy control males (n = 10). Additionally, we compared the degree of structural deviations from normal volumes of gray matter (GM) and cerebrospinal fluid (CSF) in the dorsolateral prefrontal cortex.
Compared to controls, schizophrenia and bipolar patients presented decreased NAA to creatine ratios, while only the schizophrenia group showed an increase in CSF in the dorsolateral prefrontal region. There were no differences in choline to creatine ratios among the groups.
These data suggest that the decrease in NAA in the prefrontal region may be similar in schizophrenia and bipolar disorder, at least in the chronic state. However, cortical CSF may be markedly increased in schizophrenia patients.
Brain volume abnormalities and oxidative cell damage have been reported to be pathological characteristics of schizophrenia patients. This study aims to assess a potential relationship between these two characteristics in child and adolescent patients with first-episode psychosis.
26 child and adolescent patients with first-episode early-onset schizophrenia, and 78 age- and gender-matched healthy controls were assessed. Magnetic resonance imaging (MRI) scans were used for volumetric measurements of five cerebral regions: gray matter of the frontal, parietal, and temporal lobes, sulcal cerebrospinal fluid (CSF), and lateral ventricles. Oxidative cell damage was traced by means of a systemic increase in lipid hydroperoxides (LOOH).
Lateral ventricle volumes were significantly higher in schizophrenia patients than in controls. In schizophrenia patients, a significant positive relationship was found between oxidative cell damage (LOOH levels) and the abnormal enlargement of the lateral ventricles, after controlling for total intracranial volume, age, gender, daily smoking status, intelligence quotient (IQ), psychopathology, and time since onset of psychotic symptoms. No association was found between brain volumes and oxidative cell damage in control subjects.
Our results suggest that, in patients with first-episode early-onset schizophrenia, enlargement of the lateral ventricles is associated with chronic oxidative cell damage.
Diagnosis of schizophrenia spectrum disorders (SSD) may be difficult in clinical practice, particularly during the first episodes of early-onset psychosis (FE-EOP).
To develop a Support Vector Machine (SVM) algorithm as a predictive tool for diagnostic outcome in patients with FE-EOP, based on clinical and biomedical data at the emergence of the illness.
Two-year, prospective longitudinal study, where 81 patients (9-17 years of age) with a FE-EOP and stable diagnosis at follow-up and 41 age and sex-matched healthy controls (HC) were included. Structured diagnostic interviews, clinical and cognitive scales, a MRI scan and biochemical tests were conducted at baseline. Three SVM classification algorithms were developed (SSD vs HC group, non-SSD vs HC group, and SSD vs non-SSD group). Jackknifing was used to validate the algorithms and to calculate performance estimates. Enhanced-Recursive Feature Elimination was performed in order to gain information about the predictive weight for diagnosis of each variable.
The SSD-versus-non-SSD classifier achieved an overall accuracy of 83.1%, sensitivity of 86.6% and specificity of 77.8%. The variables during a FE-EOP with higher predictive value for a diagnosis of SSD were clinical variables such as negative symptoms preceding or during the psychotic onset, poor insight and duration of illness until first psychiatric contact. Biochemical, neuroimaging, and cognitive variables at baseline did not provide any additional predictive value.
SVM may serve as a predictive tool for early diagnosis of SSD during a FE-EOP. The most discriminative variables during a FE-EOP for a future diagnosis of SSD are clinical variables.
Autism Spectrum Disorders (ASD) and psychosis share deficits in social cognition. The insular region has been associated with awareness of self and reality, which may be basic for proper social interactions.
Total and regional insular volume and thickness measurements were obtained from a sample of 30 children and adolescents with ASD, 29 with early onset first-episode psychosis (FEP), and 26 healthy controls (HC). Total, regional, and voxel-level volume and thickness measurements were compared between groups (with correction for multiple comparisons), and the relationship between these measurements and symptom severity was explored.
Compared with HC, a shared volume deficit was observed for the right (but not the left) anterior insula (ASD: p = 0.007, FEP: p = 0.032), and for the bilateral posterior insula: (left, ASD: p = 0.011, FEP: p = 0.033; right, ASD: p = 0.004, FEP: p = 0.028). A voxel-based morphometry (VBM) conjunction analysis showed that ASD and FEP patients shared a gray matter volume and thickness deficit in the left posterior insula. Within patients, right anterior (r = −0.28, p = 0.041) and left posterior (r = −0.29, p = 0.030) insular volumes negatively correlated with the severity of insight deficits, and left posterior insular volume negatively correlated with the severity of ‘autistic-like’ symptoms (r = −0.30, p = 0.028).
The shared reduced volume and thickness in the anterior and posterior regions of the insula in ASD and FEP provides the first tentative evidence that these conditions share structural pathology that may be linked to shared symptomatology.
Thalamic volume deficits are associated with psychosis but it is unclear whether the volume reduction is uniformly distributed or whether it is more severe in particular thalamic regions.
To quantify whole and regional thalamic volume in males with early-onset psychosis and healthy male controls.
Brain scans were obtained for 80 adolescents: 46 individuals with early-onset psychosis with a duration of positive symptoms less than 6 months and 34 healthy controls. All participants were younger than 19 years. Total thalamic volumes were assessed using FreeSurfer and FSL-FIRST, group comparisons of regional thalamic volumes were studied with a surface-based approach.
Total thalamic volume was smaller in participants with early-onset psychosis relative to controls. Regional thalamic volume reduction was most significant in the right anterior mediodorsal area and pulvinar.
In males with minimally treated early-onset psychosis, thalamic volume deficits may be most pronounced in the anterior mediodorsal and posterior pulvinar regions, adding strength to findings from post-mortem studies in adults with psychosis.
El estudio de la concentración de N-acetil-aspartato (NAA) proporciona datos interesantes sobre las alteraciones corticales en las enfermedades psicóticas. Aunque la reducción de la concentración de NAA en la corteza cerebral es un resultado habitual en la esquizofrenia crónica, es menos constante en la enfermedad bipolar. Por otra parte, es probable que los valores de NAA puedan ser diferente en hombres y mujeres con esquizofrenia.
Mediante con espectroscopia por resonancia magnética protónica ('H MRS) calculamos las concentraciones de NAA en la corteza prefrontal de dos grupos de hombres, uno con esquizofrenia (n = 11) y otro con trastorno bipolar (n = 13) de similar duración y los comparamos con una muestra de hombres sanos que usamos como grupo control (n = 10). Además, comparamos el grado de desviaciones estructurales de los volúmenes normales de sustancia gris (SG) y líquido cefalorraquídeo (LCR) en la corteza prefrontal dorsolateral.
Comparados con los controles, los pacientes con esquizofrenia y trastorno bipolar tuvieron un cociente NAA/creatina más bajo, y sólo el grupo de pacientes con esquizofrenia mostró un aumento de LCR en la región prefrontal dorsolateral. No hubo ninguna diferencia entre los grupos en el cociente colina/creatina.
Estos datos sugieren que la disminución de NAA en la región prefrontal pueda ser similar en la esquizofrenia y en el trastorno bipolar, al menos, en estados crónicos. Sin embargo, el LCR cortical puede aumentar significativamente en pacientes con esquizofrenia.
Decreased metabolic activity in the prefrontal cortex during cognitive activation is a recurrent finding and a likely functional marker of schizophrenia.
To investigate the occurrence of hypofrontality in patients with first-episode psychosis, with or without evolution to schizophrenia.
We used fluorodeoxyglucose positron emission tomography during the performance of an attention task and magnetic resonance imaging to study the dorsolateral prefrontal region in 13 men with a first episode of psychosis. Data from patients who progressed to schizophrenia were compared with those of patients who did not meet criteria for this diagnosis after 2 years.
Patients who developed schizophrenia demonstrated a significant hypofrontality in the dorsolateral prefrontal cortex in comparison with the non-schizophrenia and control groups.
Our results suggest that hypofrontality could be a marker of schizophrenia at the time of the first psychotic episode, in agreement with neurodevelopmental theories of schizophrenia.
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