近日，一项发表在《美国科学院院报》（PNAS）上的研究提出，儿童期遭到虐待可能破坏神经组织的发育，因此受害者——即便是成年之后——可能表现出大脑特定区域的容量减少。
虐待儿童的情况在美国比较突出，每年有4500多名儿童因为受虐待而住院，其中约300人因所受伤害过于严重而死亡。美国耶鲁大学医学院的学者分析了美国卫生保健研究与质量局2006年儿童住院数据库后发现，美国当年共有4569名儿童因为遭严重虐待而住院接受治疗，其中1岁以下的儿童比例最高。每10万名1岁以下儿童中，就有58.2人因受虐严重而住院。专家指出，这些数据比美国儿童患婴儿猝死综合征的比例还高。
Martin Teicher及其同事征召了193名未经治疗的年龄在18到25岁的成年人参与该研究。这组科研人员首先进行了访谈从而确定这些受试者在童年期是否目击过暴力或者曾经暴露于身体或性的虐待、身体或精神的忽视、严重的分离或丧失、语言虐待，或者父母的争吵。这些受试者然后接受了大脑MRI扫描，以及通过成像软件进行大脑容量测量。
与其他受试者相比，那些受到儿童期虐待的受试者的海马区的3个关键部分的容量减少了5.8%到6.5%。海马区是与情感、记忆以及其他功能有联系的一个大脑区域。科研人员此前确定了在未成熟而非成年的海马区的3个细胞群对压力做出响应而释放出一种激素。这组作者提出，让发育中的海马区接触过量的这种激素可能影响神经元发育，这可能减少脑容量。
作者说，这种改变可能有助于揭示为什么与虐待有关的早期逆境常常导致之后许多的精神疾病，诸如抑郁症、毒品成瘾以及其他精神卫生问题。（生物谷Bioon.com）
doi:10.1073/pnas.1115396109
PMC:
PMID:
Childhood maltreatment is associated with reduced volume in the hippocampal subfields CA3, dentate gyrus, and subiculum
Martin H. Teichera,b,1,2, Carl M. Andersona,b,c,1, and Ann Polcaria
Childhood maltreatment or abuse is a major risk factor for mood, anxiety, substance abuse, psychotic, and personality disorders, and it is associated with reduced adult hippocampal volume, particularly on the left side. Translational studies show that the key consequences of stress exposure on the hippocampus are suppression of neurogenesis in the dentate gyrus (DG) and dendritic remodeling in the cornu ammonis (CA), particularly the CA3 subfield. The hypothesis that maltreatment is associated with volume reductions in 3-T MRI subfields containing the DG and CA3 was assessed and made practical by newly released automatic segmentation routines for FreeSurfer. The sample consisted of 193 unmedicated right-handed subjects (38% male, 21.9 ± 2.1 y of age) selected from the community. Maltreatment was quantified using the Adverse Childhood Experience study and Childhood Trauma Questionnaire scores. The strongest associations between maltreatment and volume were observed in the left CA2-CA3 and CA4-DG subfields, and were not mediated by histories of major depression or posttraumatic stress disorder. Comparing subjects with high vs. low scores on the Childhood Trauma Questionnaire and Adverse Childhood Experience study showed an average volume reduction of 6.3% and 6.1% in the left CA2-CA3 and CA4-DG, respectively. Volume reductions in the CA1 and fimbria were 44% and 60% smaller than in the CA2-CA3. Interestingly, maltreatment was associated with 4.2% and 4.3% reductions in the left presubiculum and subiculum, respectively. These findings support the hypothesis that exposure to early stress in humans, as in other animals, affects hippocampal subfield development.
