Journal of psychiatric research
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The goals of this study were to first determine whether the fractional anisotropy (FA) and mean diffusivity (MD) of major white matter pathways associate with schizophrenia, and secondly to characterize the extent to which differences in these metrics might reflect a genetic predisposition to schizophrenia. Differences in FA and MD were identified using a comprehensive atlas-based tract mapping approach using diffusion tensor imaging and high-resolution structural data from 35 patients, 28 unaffected first-degree relatives of patients, 29 community controls, and 14 first-degree relatives of controls. Schizophrenia patients had significantly higher MD in the following tracts compared to controls: the right anterior thalamic radiations, the forceps minor, the bilateral inferior fronto-occipital fasciculus (IFO), the temporal component of the left superior longitudinal fasciculus (tSLF), and the bilateral uncinate. ⋯ Diffusion tensor imaging studies have previously identified white matter abnormalities in all three of these tracts in schizophrenia; however, this study is the first to identify a significant genetic liability. Thus, FA of these three tracts may serve as biomarkers for studies seeking to identify how genes influence brain structure predisposing to schizophrenia. However, differences in FA and MD in frontal and temporal white matter pathways may be additionally driven by state variables that involve processes associated with the disease.
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Epigenetic alterations of the brain-derived neurotrophic factor (Bdnf) gene have been linked with memory, stress, and neuropsychiatric disorders. Here we examined whether there was a link between an established rat model of post-traumatic stress disorder (PTSD) and Bdnf DNA methylation. Adult male Sprague-Dawley rats were given psychosocial stress composed of two acute cat exposures in conjunction with 31 days of daily social instability. ⋯ In addition, there were decreased levels of Bdnf mRNA in both the dorsal and ventral CA1. These results provide evidence that traumatic stress occurring in adulthood can induce CNS gene methylation, and specifically, support the hypothesis that epigenetic marking of the Bdnf gene may underlie hippocampal dysfunction in response to traumatic stress. Furthermore, this work provides support for the speculative notion that altered hippocampal Bdnf DNA methylation is a cellular mechanism underlying the persistent cognitive deficits which are prominent features of the pathophysiology of PTSD.
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Although, a large population-based literature exists on the relationship between childhood adversity and Axis I mental disorders, research on the link between childhood adversity and Axis II personality disorders (PDs) relies mainly on clinical samples. The purpose of the current study was to examine the relationship between a range of childhood adversities and PDs in a nationally representative sample while adjusting for Axis I mental disorders. ⋯ Further research is necessary to understand whether such exposure has a causal role in the association with PDs. In addition to preventing child maltreatment, it is important to determine ways to prevent impairment among those exposed to adversity, as this may reduce the development of PDs.
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Recent epidemiologic studies have found an increased risk of suicide among Veterans of Operations Enduring Freedom and Iraqi Freedom (OEF-OIF) with psychiatric disorders. However, little is known about whether variables other than psychiatric conditions, such as coping strategies, resilience, and social support, may be related to suicidality in this population. ⋯ 1 in 5 treatment-seeking OEF-OIF Veterans may contemplate suicide. Interventions to reduce depressive symptoms, and maladaptive cognitive-behavioral coping strategies of self-punishment and cognitive social avoidance, and to bolster psychological resilience may help mitigate suicidality in this population.
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Pilot studies represent a fundamental phase of the research process. The purpose of conducting a pilot study is to examine the feasibility of an approach that is intended to be used in a larger scale study. The roles and limitations of pilot studies are described here using a clinical trial as an example. ⋯ Pilot results can inform feasibility and identify modifications needed in the design of a larger, ensuing hypothesis testing study. Investigators should be forthright in stating these objectives of a pilot study. Grant reviewers and other stakeholders should expect no more.