Psychiatry research
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Psychiatry research · Oct 2009
Anatomical brain connectivity and positive symptoms of schizophrenia: a diffusion tensor imaging study.
Structural brain changes in schizophrenia are well documented in the neuroimaging literature. The classical morphometric analyses of magnetic resonance imaging (MRI) data have recently been supplemented by diffusion tensor imaging (DTI), which mainly assesses changes in white matter (WM). DTI increasingly provides evidence for abnormal anatomical connectivity in schizophrenia, most often using fractional anisotropy (FA) as an indicator of the integrity of WM tracts. ⋯ The arcuate fasciculus was the only tract which showed increased FA values in patients. Increased FA values in this region correlated with increased severity of auditory hallucinations and length of illness. Our results suggest that local changes in anatomical integrity of WM tracts in schizophrenia may be related to patients' clinical presentation.
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Chronic marijuana use during adolescence is frequently comorbid with heavy alcohol consumption and associated with CNS alterations, yet the influence of early cannabis and alcohol use on microstructural white matter integrity is unclear. Building on evidence that cannabinoid receptors are present in myelin precursors and affect glial cell processing, and that excessive ethanol exposure is associated with persistently impaired myelination, we used diffusion tensor imaging (DTI) to characterize white matter integrity in heavy substance using and non-using adolescents. We evaluated 36 marijuana and alcohol-using (MJ+ALC) adolescents (ages 16-19) and 36 demographically similar non-using controls with DTI. ⋯ Findings suggest that fronto-parietal circuitry may be particularly impacted in adolescent users of the most prevalent intoxicants: marijuana and alcohol. Disruptions to white matter in this young group could indicate aberrant axonal and myelin maturation with resultant compromise of fiber integrity. Findings of increased anisotropic diffusion in alternate brain regions suggest possible neuroadaptive processes and can be examined in future studies of connectivity to determine how aberrancies in specific tracts might influence efficient cognitive processing.
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Psychiatry research · Sep 2009
Gray matter abnormalities in subjects at ultra-high risk for schizophrenia and first-episode schizophrenic patients compared to healthy controls.
Neuroimaging studies have revealed gray matter abnormalities in schizophrenia in various regions of the brain. It is, however, still unclear whether such abnormalities are already present in individuals at ultra-high risk (UHR) for transition into psychosis. We investigated this issue using voxel-based morphometry of structural magnetic resonance images (MRI) and compared UHR patients with first-episode patients with schizophrenia and healthy controls. ⋯ UHR patients showed significantly lower gray matter volume in the cingulate gyrus bilaterally, in the right inferior frontal and right superior temporal gyrus, as well as in the left and right hippocampus in comparison to healthy subjects. First-episode patients with schizophrenia showed smaller gray matter volume in the cingulate cortex bilaterally, in the left orbitofrontal gyrus, in the right inferior frontal and superior temporal gyrus, in the right temporal pole, in the left and right hippocampus, in the left parahippocampus, left amygdala, and in the left fusiform gyrus compared to the UHR patients. This study provides further evidence that gray matter brain volume, especially in the anterior cingulate cortex, is already reduced in the prodromal state of schizophrenia.
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Psychiatry research · Sep 2009
Preventing suicide and homicide in the United States: the potential benefit in human lives.
In order to assess the potential benefit in human lives if all geographical regions in the US (Northeast, South, Midwest, and West) achieved the lowest suicide and homicide rates observed within these regions, age-, race- and gender-adjusted suicide and homicide rates for each of the four regions were calculated based on data retrieved using the Centers for Disease Control and Prevention database for 1999-2004. Data on known risk factors were retrieved from online sources. Overall suicide rates (10.42 per 100,000) exceeded homicide rates (6.97 per 100,000). ⋯ In the total estimate of avoidable deaths, firearm suicides (90%) and firearm homicides (75%) were overrepresented. The Northeast had the lowest access to firearms (20%) contrasted to almost double in the other regions, whereas greater firearms availability was related to unrestricted firearm legislation. Measures to restrict firearms availability should be highly prioritized in the public health agenda in order to achieve an impressive benefit in human lives.
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Psychiatry research · Aug 2009
Validity of cognitive complaints in substance-abusing patients and non-clinical controls: the Patient's Assessment of Own Functioning Inventory (PAOFI).
To determine the validity of substance-abusing (SA) patients' self-reports of cognitive impairments, we assessed the independent contributions of depression, actual neurocognitive performance and an index of cognitive decline, in predicting cognitive complaints in groups of SA patients and normal controls. The SA sample comprised 74 veterans enrolled in day treatment. The non-clinical sample consisted of 150 English-speaking adults. ⋯ BDI scores accounted for 12% of the variance in PAOFI total score for the SA sample and 44% for the non-clinical sample in multiple regression analysis. Cognitive complaints were related more to depression than cognitive performance for both SA and non-clinical samples. The results do not support self-report as a valid means of neuropsychological assessment in SA samples, although self-reports may provide other information about perceived cognitive difficulties that may be relevant to clinical evaluation.