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Posttraumatic stress disorder (PTSD) is a relatively common and predictable psychological syndrome (Miller, 1999). PTSD occurs in a proportion of individuals exposed to severe psychological trauma (Kasai et al., 2006) and in which the individual responds with fear, helplessness, or horror (Danckwerts & Leathem, 2003). Individuals with PTSD suffer from intrusive memories about the traumatic event, persistent avoidance of stimuli associated with the trauma, and persistent symptoms of increased arousal. These symptoms become uncontrollable and disabling (Bremner & Charney, 1994) that serious threaten human health and social function. Due to its debilitating nature, PTSD has emerged as an important public health problem in the general population (Sareen et al., 2007). In recent years, a great deal of research has been directed towards understanding the etiology, phenomenology, neurobiology, clinical characteristics and treatment of PTSD (Nemeroff et al., 2006). However, a number of core psychological processes underlying PTSD have yet to be elucidated (Shin et al., 2006; Liberzon & Sripada, 2008). Over the past decade, findings from neuroimaging studies have allowed for tremendous advances in our understanding of the experience of emotions in healthy individuals and the dysregulation of these processes associated with PTSD. These studies have been useful in both generating hypotheses on the neurobiology of normative human responses to trauma and complementing our understanding of the wide-ranging alterations in trauma survivors who develop PTSD. Structural neuroimaging studies have focused primarily on hippocampal volumetry (Geuze et al., 2005) as well as the prefrontal cortex (Geuze et al., 2008a) and other brain structures. Hippocampal morphology has been correlated with severity of PTSD symptomatology (Gilbertson et al., 2002; Villarreal & King, 2004). However, the results have been inconsistent, with studies reporting significant reductions or increases, as well as unchanged volumes. For example, studies have shown that patients with PTSD are associated with bilateral lower hippocampal volume (Bossini & Castrogiovanni, 2007; Bremner et al., 2003; Emdad et al., 2006; Lindauer et al., 2004a; Vythilingam et al., 2005; Li et al., 2006), which are

Internet addition disorder (IAD) is currently becoming a serious mental health problem among Chinese adolescents. The pathogenesis of IAD, however, remains unclear. The purpose of this study applied regional homogeneity (ReHo) method to analyze encephalic functional characteristic of IAD college students under resting state.Functional magnetic resonanc image (fMRI) was performed in 19 IAD college students and 19 controls under resting state. ReHo method was used to analyze the differences between the average ReHo in two groups.The following increased ReHo brain regions were found in IAD group compared with control group: cerebellum, brainstem, right cingulate gyrus, bilateral parahippocampus, right frontal lobe (rectal gyrus, inferior frontal gyrus and middle frontal gyrus), left superior frontal gyrus, left precuneus, right postcentral gyrus, right middle occipital gyrus, right inferior temporal gyrus, left superior temporal gyrus and middle temporal gyrus. The decreased ReHo brain regions were not found in the IAD group compared with the control group.There are abnormalities in regional homogeneity in IAD college students compared with the controls and enhancement of synchronization in most encephalic regions can be found. The results reflect the functional change of brain in IAD college students. The connections between the enhancement of synchronization among cerebellum, brainstem, limbic lobe, frontal lobe and apical lobe may be relative to reward pathways.

On July 29, 2007, a severe coalmine-flooded disaster occurred in central China and 69 miners were trapped in an about 1400 m underground coal pit. Fortunately, all of them were rescued after 75 h of the ordeal. At 3 and 6 months after the disaster, psychopathological profiles, plasma levels of cortisol and adrenocorticotropic hormone (ACTH) were evaluated in 48 survivors for posttraumatic stress disorder (PTSD) and comorbid symptoms. Magnetic resonance imaging (MRI) study was performed at 6 months. The prevalence of PTSD was 35.4% (17/48) at 3 months and 31.3% (15/48) at 6 months post-disaster, with high rates of comorbid symptoms. Risk factors for PTSD included previous traumatic experience, less than 5 years of being a miner, in an extremely exhausted or sick during the disaster, poor interpersonal relationship and poor sleep quality experienced before the disaster. Mean plasma cortisol levels at 6 months, but not at 3 months, were significantly higher in PTSD-positive subjects than the negative, and positively correlated with the severity of several comorbid symptoms. Either whole or regional brain volumes of PTSD-positive subjects were not significantly different from PTSD-negative subjects, but PTSD subjects had significantly reduced fractional anisotropy values in the right posterior cingulum and bilateral hippocampal body compared to subjects without PTSD. These results suggest that traumatic exposure in severe coalmining disasters results in considerable psychological consequences, with highly prevalent PTSD and comorbid symptoms, which are associated with previous traumatic experience, shorter-length underground services, and poor interpersonal relationships and sleep quality experienced before the disaster. Baseline cortisol level may be a useful biological predictor for different phases of the development of PTSD. The aberrant connectivity of the hippocampus and the cingulum may represent an early pathological response to trauma exposure.