Study suggests females are more sensitive to chronic stress than males

A recent study conducted by researchers at the Federal University of Rio de Janeiro (UFRJ) investigated whether men and women experience chronic stress differently. Using a model of chronic unpredictable mild stress (CUMS) on Swiss mice, the research aimed to understand if male and female rodents react to prolonged stress at different rates and times. The experiment involved exposing adult male and female mice to four, six, or eight weeks of moderate, unpredictable chronic stress. Following this period, behavioral assessments and serum corticosterone levels were measured. Corticosterone is the rodent equivalent of cortisol, the primary stress hormone in humans. The findings indicated a significant difference between sexes, primarily related to timing. While both males and females exhibited anxiety-related behaviors early in the stress period, their responses diverged. Females displayed more pronounced anxiety and depression-related behavioral changes. Specifically, depressive behaviors, characterized by reduced responsiveness to difficult situations, only emerged in females after two months of continuous stress. Furthermore, only female mice showed an increase in stress hormone levels. These results suggest that females may be more susceptible to the detrimental effects of chronic stress compared to males, mirroring clinical observations in humans where women are more prone to stress-induced adverse outcomes like anxiety and depression. The study utilized Swiss mice, which have broader genetic variation than isogenic strains, thus better mimicking human genetic variability. This research was supported by grants from the National Council for Scientific and Technological Development (CNPq), the Carlos Chagas Filho Foundation for Research Support of the State of Rio de Janeiro, and the Coordination for the Improvement of Higher Education Personnel (Capes).