Background:Childhood trauma (CT) has been linked to increased risk for mental illness in
adulthood. Although work in experimental animals has shown that early life stressors can
affect inhibitory and excitatory neurotransmission in adult rodents, with possible
excitotoxic effects on local grey matter volumes (GMV), the neurobiological mechanisms
that mediate this relationship in humans remain poorly understood.Aim:To examine glutamate and gamma-aminobutyric acid (GABA) metabolite concentrations and
potential excitotoxic effects on GMV, in adults who experienced CT.Methods:Fifty-six young adults (Mage= 20.41) were assigned to High
CT (n= 29) and Low CT (n= 27) groups (by using the
CT questionnaire) and underwent magnetic resonance spectroscopy (1H-MRS) to
measure temporal lobe metabolite concentrations and volumetric imaging to measure
GMV.Results:Glutamate concentrations did not differ between groups; however, relative to the Low CT
group, participants in the High CT group had reduced GABA concentrations in the left
superior temporal gyrus (STG) voxel. Furthermore, logistic regression showed that
participants with low left STG GABA concentrations and low left STG volumes were
significantly more likely to be in the high CT group.Conclusions:This study provides the first evidence that both low GABA concentrations and its
interaction with GMV in the left STG are associated with high levels of CT and suggest
that altered inhibitory neurotransmission/metabolism may be linked to a lower GMV in the
left STG in adults who experienced CT. Future studies are warranted to establish if
utilizing these measures can stratify clinical high-risk and predict future clinical
outcomes in high CT individuals.