Social stress, cortisol awakening response and sex: Impact on hippocampus and amygdala volume

Abstract

ObjectiveVolumes of the hippocampus and amygdala, both major hubs for neural stress regulation amongst others, are influenced by social stressors, cortisol awakening response (CAR) and sex, i.e. psychological and physiological stress factors. Importantly, the interplay of these different factors in affecting the morphology of both brain regions remains unclear. This study aimed to elucidate the intricate influence of these factors on grey matter volumes (GMV) of the hippocampus and amygdala. MethodsWe analyzed associations between structural brain data, self-reported chronic social stress (including subscales on social tension, social overload, lack of social recognition and social isolation) and CAR of 83 healthy participants (40 females) with multiple regression analyses. ResultsIn males, but not females, higher social tension predicted lower bilateral hippocampus GMV. In individuals not showing the typical CAR, higher social tension predicted reduced bilateral hippocampus GMV. Amygdala GMV was also related to social stress and CAR, with social overload associated with reduced amygdala GMV in individuals not showing the typical CAR, while the opposite pattern emerged in those with an atypical CAR. ConclusionsChronic social stress is associated with hippocampus and amygdala volumes, interacting with CAR and sex. The brain morphology in males and in individuals with atypical CAR seems to be more vulnerable to chronic social stress. Our findings enhance our understanding of how brain architecture, social stress, CAR patterns and sex shape individual stress responses.