The fact that women are the more stressed sex may not be a surprise. The numbers alone tell a compelling story -- women are two times more likely to suffer from depression, post-traumatic stress disorder and other stress-related disorders.

Now, neuroscientists have discovered women may be wired to be more sensitive to stress.

The study, performed on rats, involved a hormone secreted in the brain, called corticotropin-releasing factor, which orchestrates the body's response to stress. For those with stress-related disorders, such as depression and anxiety, the evidence suggests that the hormone malfunctions in some way, causing a person to feel overly emotional, anxious or fearful.

In the study lead investigators Rita Valentino and Debra Bangasser showed that female rats were vulnerable to levels of CRF that were too low to affect male rats.