Some environmental stressors lead to the onset of depression via inhibiting hippocampal BDNF expression, but other environmental stressors-induced depression exhibits no change in BDNF expression. The underlying mechanisms behind the divergence remain unknown. In this study, depression-like behaviors were induced in rats by maternal deprivation (MD) and chronic unpredictable stress (CUPS). Depression-like behaviors were tested by open field test, forced swimming test, and sucrose consumption test. BDNF and miR-16 expressions in the hippocampus were examined by real-time PCR. MD and CUPS rats crawled less distance, exhibited decreased vertical activity, and produced more fecal pellets than control rats in the open field test. However, MD rats crawled less distance and produced significantly less fecal pellets than CUPS rats. In the forced swimming and sucrose consumption tests, CUPS and MD rats exhibited longer floating time and consumed less sucrose than control rats, but MD rats exhibited shorter floating time and consumed less sucrose than CUPS rats. MD but not CUPS rats showed lower BDNF mRNA and higher miR-16 expression than control rats. In MD rats, BDNF mRNA expression negatively correlated with the expression of miR-16. BDNF expression positively correlated with the total distance rats crawled and vertical activity in the open field test while miR-16 expression negatively correlated the two behaviors. BDNF positively correlated with sucrose preference rate while miR-16 negatively correlated with sucrose preference rate of the sucrose consumption test. Our study suggests that MD and CUPS induced different depression-like behaviors in rats. Depression induced by MD but not CUPS was significantly associated with upregulation of miR-16 and possibly subsequent downregulation of BDNF in hippocampus.

Background Most studies have shown that insecure attachment and stress are important risk factors in the development of depression and anxiety. However, it is unclear whether distinct patterns of insecure attachment may relate differently to depression and anxiety following stressful events. Thus, the current study examined whether anxious and avoidant attachment, both of which are operationalized as insecure attachment, predict depressive and anxious symptoms following the occurrence of hassles. Method A sample of 662 Chinese university students was recruited from Hunan, China. At the initial assessment, participants completed self-report measures assessing insecure attachment (i.e. anxious and avoidant attachment), hassles, anxious symptoms, and depressive symptoms. Additionally, hassles and symptoms of anxiety and depression were assessed once a month for the subsequent 6 months. Results The results of hierarchical linear modeling analyses indicated a significant interaction between anxious attachment and hassles in predicting follow-up depressive symptoms. Specifically, participants with high levels of anxious, but not avoidant, attachment reported high levels of depressive symptoms when experiencing high, as opposed to low, levels of hassles. At the same time, while both anxious and avoidant attachment predicted higher levels of anxious symptoms over time, a cross-level, significant interaction did not emerge. Conclusions Insecure attachment styles serve as a vulnerability factor in the development of depressive and anxious symptoms in Chinese young adults. Consequently, fostering the development of secure attachment in prevention and intervention programs may, ultimately, prevent the onset and maintenance of depressive and anxious disorders. Depression and Anxiety 00:1–8, 2012.

Early life stress has been demonstrated to increase the risk of developing depression in adulthood. However, the roles and associated molecular mechanisms of stresses in the onset and relapse of depression have yet to be fully elucidated. Depression-like behaviors were induced in rats by maternal deprivation and chronic unpredictable stress. Depression- and anxiety-like behaviors of rats, dopamine receptor D2 level, and microRNAs expression in rats’ brain tissues were measured. Chronic unpredictable stress alone induced depression-like behaviors in rats, but maternal deprivation enhanced the effect of chronic unpredictable stress. Escitalopram significantly decreased depression-like behaviors in chronic unpredictable stress rats but was less effective in maternal deprivation with chronic unpredictable stress rats. Maternal deprivation increased dopamine receptor D2 messenger RNA expression and decreased microRNA-9 expression in the striatum. Chronic unpredictable stress increased dopamine receptor D2 mRNA and protein levels and decreased microRNA-9 expression in the nucleus accumbens. Furthermore, maternal deprivation enhanced the effect of chronic unpredictable stress on dopamine receptor D2 gene and microRNA-9 expression. Chronic unpredictable stress increased the expression of microRNA-326 in the nucleus accumbens but decreased it in the striatum, whereas maternal deprivation elevated microRNA-326 expression in the striatum. Escitalopram normalized microRNA-326 expression but had no effect on the expression of microRNA-9, dopamine receptor D2 mRNA, and dopamine receptor D2 protein in both the nucleus accumbens and striatum. The in vitro study showed that only microRNA-9 directly targeted the 3’ untranslated region of dopamine receptor D2 mRNA and inhibited dopamine receptor D2 protein expression. Early life stress enhanced the susceptibility to late life stress and resistance to escitalopram treatment through decreasing microRNA-9 expression and subsequently upregulating dopamine receptor D2 expression in the nucleus accumbens. microRNA-326 may be a novel target of escitalopram.

Background: Although there are accumulating data regarding the epidemiology of suicide in China, there are meager data on suicidal ideation and attempts among college students. Interestingly, elevated impulsivity is thought to facilitate the transition from suicidal thoughts to suicidal behavior. Therefore, the objective of this research was to identify the associations between suicide and the personality factors of impulsivity and aggression. Methods: This study’s sampling method employed stratified random cluster sampling. A multi-stage stratified sampling procedure was used to select participants (n = 5,245). We conducted structured interviews regarding a range of socio-demographic characteristics and suicidal morbidity. The Patient Health Questionnaire depression module (PHQ-9) was used to acquire the information about thoughts of being better off dead or hurting themselves in some ways during the past two weeks. The impulsivity symptoms in this study were assessed with the BIS-11-CH (i.e., the Chinese version of the BIS-11), and the Aggressive symptoms were assessed with the BAQ. The statistical package for social science (SPSS) v.13.0 program (SPSS Inc., Chicago, IL, USA) was used for statistical analysis. Socio-demographic variables such as ethnic and gender were compared between groups, through the use of χ ² tests. The nonparametric test (k Independent Sample test, Kruskal-Wallis H) was performed to determine differences between the personality factors of impulsivity and aggression and suicide. Results: In total, 9.1% (n = 479) of the 5,245 students reported they have ever thought about committing suicide; and 1% (n = 51) reported a history of attempted suicide (attempters). The analyses detected significant differences in scores on cognitive impulsivity (p < 0.01), when comparing individuals who only had suicidal ideation and individuals who had attempted suicide. Moreover, significant differences were found between ideators only and attempters on scores of self-oriented attack (p < .001). Conclusions: Suicidal ideation is prevalent among Chinese university students. Students with high aggression scores were more susceptible to committing suicide. Scores on self-oriented attack and cognitive impulsivity may be important factors for differentially predicting suicide ideation and suicide attempts.