University of California, Los Angeles, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095-1563, USA.
Neuroscience. 2013 Sep 26;249:129-38. doi: 10.1016/j.neuroscience.2012.12.010. Epub 2012 Dec 20.
Depression is a common outcome for those having experienced early-life stress (ELS). For those individuals, depression typically increases during adolescence and appears to endure into adulthood, suggesting alterations in the development of brain systems involved in depression. Developmentally, the nucleus accumbens (NAcc), a limbic structure associated with reward learning and motivation, typically undergoes dramatic functional change during adolescence; therefore, age-related changes in NAcc function may underlie increases in depression in adolescence following ELS. The current study examined the effects of ELS in 38 previously institutionalized children and adolescents in comparison to a group of 31 youths without a history of ELS. Consistent with previous research, the findings showed that depression was higher in adolescents than children with a history of ELS. Additionally, functional magnetic resonance imaging results showed atypical NAcc development, where the ELS group did not show a typical increase in NAcc reactivity during adolescence. Consequently, the ELS group showed NAcc hypoactivation during adolescence, and lower NAcc reactivity was correlated with higher depression scores. The results have important implications for understanding how ELS may influence increases in depression via neural development during the transition to adolescence and highlight the importance of identifying at-risk individuals in childhood, a potential critical period for depression-targeted intervention.
抑郁症是经历早期生活压力(ELS)的人的常见后果。对于这些人来说,抑郁症通常在青春期加重,并似乎持续到成年期,这表明与抑郁症相关的大脑系统发育发生了变化。从发育的角度来看,伏隔核(NAcc)是与奖励学习和动机相关的边缘结构,通常在青春期经历剧烈的功能变化;因此,ELS 后青春期抑郁的增加可能与 NAcc 功能的年龄相关变化有关。本研究比较了 38 名曾被机构收容的儿童和青少年与 31 名无 ELS 病史的青少年,研究了 ELS 的影响。与先前的研究一致,研究结果表明,有 ELS 病史的青少年的抑郁程度高于儿童。此外,功能磁共振成像结果显示 NAcc 发育异常,ELS 组在青春期期间 NAcc 反应性没有典型增加。因此,ELS 组在青春期时 NAcc 活动减弱,而 NAcc 反应性越低,抑郁评分越高。这些结果对于理解 ELS 如何通过青春期向成年期的神经发育影响抑郁的增加具有重要意义,并强调了在儿童期识别高危个体的重要性,这是针对抑郁症进行干预的潜在关键时期。