The researchers found that male participants had greater cerebral blood flow in their right orbitofrontal cortex and reduced bloodflow in their left orbitofrontal cortex during the high stress condition; this was accompanied by increased cortisol levels (part of the stress response).
Females in the high stress condition, on the other hand, had greater activation of the limbic system (the part of the brain that deals with emotions), but had much lower levels of cortisol.
According to Jiongjiong Wang, Ph.D.Research Assistant Professor of Radiology and Neurology at the University of Pennsylvania who carried out the study:
“Women have twice the rate of depression and anxiety disorders compared to men,” notes Dr. Wang. “Knowing that women respond to stress by increasing activity in brain regions involved with emotion, and that these changes last longer than in men, may help us begin to explain the gender differences in the incidence of mood disorders.”
He also claims that "These findings suggest that stress responses may be fundamentally different in each gender, sometimes characterized as “fight-or-flight” in men and “tend-and-befriend” in women. Evolutionarily, males may have had to confront a stressor either by overcoming or fleeing it, while women may have instead responded by nurturing offspring and affiliating with social groups that maximize the survival of the species in times of adversity. The “fight-or-flight” response is associated with the main stress hormone system that produces cortisol in the human body – the hypothalamic-pituitary-adrenal ( HPA) axis."
Males are more likely to die from stress related illnesses such as coronary heart disease, while females are more likely to suffer ill health, so these findings suggest a mechanism for these differences.
Are these sex differences or gender differences ('gender differences' suggests they are caused by social factors, while 'sex differences suggests a biological cause)?
Also, can you spot any problems with the study?
This work by Keiron Walsh is licensed under a Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales License.
