Neuroscience
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Relative to other developmental periods, adolescence is characterized by risky decision making, increased perceived stress and heightened reactivity to acute stress. It is also during this time that individuals undergo significant neurodevelopment in brain regions that process decision making and stress. In this review, we summarize what is currently known about stress during adolescence, how it impacts risky decision-making, and how acute stress may exert neurobiological effects on circuitry that subserves decision-making in the developing brain. We conclude by suggesting future research directions that may help the field gain traction on this important, but relatively understudied, question.
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The genetic, biological, and environmental backgrounds of an organism fundamentally influence the balance between risk and resilience to stress. Sex, age, and environment transact with responses to trauma in ways that can mitigate or exacerbate the likelihood that post-traumatic stress disorder will develop. Translational approaches to modeling affective disorders in animals will ultimately provide novel treatments and a better understanding of the neurobiological underpinnings behind these debilitating disorders. ⋯ Animal models of stress have differing effects on behavior and endocrine pathways; however, complete models replicating clinical characteristics of risk and resilience have not been rigorously studied. This review discusses a four-factor model that considers the importance of studying both risk and resilience in understanding the developmental response to trauma/stress. Consideration of the multifactorial nature of clinical populations in the design of preclinical models and the application of preclinical findings to clinical treatment approaches comprise the core of translational reciprocity, which is discussed in the context of the four-factor model.
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Various studies have shown that increased activity of the hypothalamic-pituitary-adrenal (HPA) axis can predict the onset of adolescent depressive symptomatology. We have previously shown that adolescents making the transition to high school present a significant increase in cortisol levels, the main product of HPA axis activation. In the present study, we evaluated whether a school-based education program developed according to the current state of knowledge on stress in psychoneuroendocrinology decreases cortisol levels and/or depressive symptoms in adolescents making the transition to high school. ⋯ The results show that only adolescents starting high school with high levels of anger responded to the intervention with a significant decrease in cortisol levels. Moreover, we found that adolescents who took part in the intervention and showed decreasing cortisol levels following the intervention (responders) were 2.45 times less at risk to suffer from clinical and subclinical depressive states three months post-intervention in comparison to adolescents who showed increasing cortisol levels following the intervention (nonresponders). This study provides the first evidence that a school-based program on stress is effective at decreasing cortisol levels and depressive symptomatology in adolescents making the transition to high school and it helps explain which adolescents are sensitive to the program and what are some of the characteristics of these individuals.
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It is well-known that the onset of puberty is associated with changes in mood as well as cognition. Stress can have an impact on these outcomes, which in many cases, can be more influential in females, suggesting that gender differences exist. The adolescent period is a vulnerable time for the onset of certain psychopathologies, including anxiety disorders, depression and eating disorders, which are also more prevalent in females. ⋯ Spatial learning and synaptic plasticity are also adversely impacted at puberty, likely a result of increased expression of α4βδ GABARs on the dendritic spines of CA1 hippocampal pyramidal cells, which are essential for consolidation of memory. This review will focus on the role of these receptors in mediating behavioral changes at puberty. Stress-mediated changes in mood and cognition in early adolescence may have relevance for the expression of psychopathologies in adulthood.
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Adolescence is a developmental period when many teenagers first drink alcohol and often engage in binge drinking. Early onset of alcohol is linked to increased risk of stress-related disorders in adulthood in humans, suggesting that alcohol may interfere with development of the stress regulatory system. We investigated the effect of voluntary alcohol exposure on corticotropin-releasing factor (CRF) peptide-producing cells in the central nucleus of the amygdala (CeA) in adolescent male and female rats. ⋯ In both males and females, alcohol self-administration reduced the number of CRF-ir cells in the CeA compared to control conditions in which rats self-administered equivalent levels of sweetened water that did not contain alcohol. Reduced peptide labeling was not observed in the bed nucleus of the stria terminalis, indicating regional specificity of these changes. Alterations within the CRF cell population of the amygdala may have important implications for susceptibility to alcohol and stress disorders during adolescence and later on in life.