Adverse childhood experiences and left hippocampal volumetric reductions: A structural magnetic resonance imaging study.

Background: Adverse childhood experiences (ACEs) have been associated with volume alterations of stress-related brain structures among aging and clinical populations, however, existing studies have predominantly assessed only one type of ACE, with small sample sizes, and it is less clear if these associations exist among a general population of young adults.

Objective: The aims were to describe structural hippocampal volumetric differences by ACEs exposure and investigate the association between ACEs exposure and left and right hippocampal volume in a student sample of young adults.

Methods: 959 young adult students (18-24 years old) completed an online questionnaire on ACEs, mental health conditions, and sociodemographic characteristics. Magnetic resonance imaging (MRI) was used to measure left and right hippocampal volume (mm). We used linear regression to explore the differences of hippocampal volumes in university students with and without ACEs.

Results: Two thirds of students (65.9%) reported ACEs exposure. As ACEs exposure increased there were significant volumetric reductions in left (p < 0.0001) and right hippocampal volume (p = 0.001) and left (p = 0.0023) and right (p = 0.0013) amygdala volume. After adjusting for intracranial brain volume, sex, age, and depression diagnosis there was a negative association between ACEs exposure and left (β = -22.6, CI = -44.5, -0.7, p = 0.0412) but not right hippocampal volume (β = -18.3, CI = -39.2, 2.6, p = 0.0792). After adjusting for intracranial volume there were no associations between ACEs exposure and left (β = -9.2, CI = -26.2, 7.9 p = 0.2926) or right (β = -5.6, CI = -19.9,8.8 p = 0.4466) amygdala volume.

Conclusions: Hippocampal volume varied by ACEs exposure in young adult students. ACEs appear to contribute to neuroanatomic differences in young adults from the general population.