Journal of psychiatric research
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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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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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Explore the unique developmental challenges and early adversity faced by youth and young adult who died of suicide. ⋯ During the last year, mood disorders, abuse and dependence disorders, and anxiety disorder were between 8 and 63 times more likely to be present in the suicide group. Between 0 and 4 years old, 50% of children in the SG were exposed to abuse, physical and/or sexual violence; 60% between 5 and 9 years old; and by the time they were 10-14 years old, 77% were exposed to these forms of violence. In the control group, the respective figures were 14%, 18% and 34%. In the suicide group, the trajectories leading to suicide are different as we observe two different subgroups, one with early-onset and one with later-onset of adversity. To a large extent, people in the suicide group were exposed to major adversity and they were more likely to present cumulative comorbid disorders.