Meta-analysis of associations between childhood adversity and hippocampus and amygdala volume in non-clinical and general population samples

Background Studies of psychiatric populations have reported associations between childhood adversity and volumes of stress-related brain structures. This meta-analysis investigated these associations in non-clinical samples and therefore independent of the effects of severe mental health difficulties and their treatment. Methods The MEDLINE database was searched for magnetic resonance imaging studies measuring brain structure in adults with and without childhood adversity. Fifteen eligible papers (1781 participants) reporting hippocampal volumes and/or amygdala volumes were pooled using a random effects meta-analysis. Results Those with childhood adversity had lower hippocampus volumes (hedges g = − 0.15, p = 0.010). Controlling for gender, this difference became less evident (hedges g = − 0.12, p = 0.124). This association differed depending on whether studies included participants with some psychopathology, though this may be due to differences in the type of adversity these studies examined. There was no strong evidence of any differences in amygdala volume. Discussion Childhood adversity may have only a modest impact on stress-related brain structures in those without significant mental health difficulties.