Men and women are different. A few decades ago, that idea made the cover of major news magazines. But researchers are frequently confronted with differences between the sexes. A recent study on the mental health condition known as Post-traumatic stress disorder (PTSD) suggests that gender differences may play a role in who is most vulnerable to developing the condition. National surveys and statistical models which predict PTSD cases say that women are far more likely than men to experience PTSD. Some experts suggest that women are as much as two times more likely to develop the condition. This could be because so many women undergo trauma. One survey says that as many as one half of women can expect to live through a serious trauma at one point during their lifetime. Since PTSD is an outgrowth of experienced trauma, researchers wondered about the links between gender and PTSD development. In reality, men are more apt than women to experience a traumatic life event. During a given year, 60 percent of men will live through a traumatic event while just 51 percent of women will do so. Nevertheless, fewer than four percent of all who experience trauma will go on to develop PTSD. All of which highlights the fact that undergoing trauma does not guarantee that a person will experience a disordered response to trauma. Since women experience fewer traumatic events but have a higher risk of developing PTSD, researchers looked for what could explain the gender gap. They found that women who had lived through violent traumas such as sexual assault, injury-causing trauma or trauma which was perceived as life-threatening, were more prone to developing PTSD. Other risk factors which affected whether a woman developed PTSD included subsequent stress events, inadequate support networks following the trauma and a history of mental illness. Emory University research further suggests that a chemical factor could help explain female susceptibility to the disorder. A hormone known as pituitary adenylate cyclase-activating polypeptide (PACAP) could be responsible for women succumbing to PTSD more often than men. That hormone showed up in significantly higher levels among women who manifested symptoms of PTSD during the study. Another reason why women may be more liable to developing PTSD is their emotional make-up. Women are known to be more prone to anxiety and depressive disorders in general. Unlike men, women tend to take personal responsibility for their victim status. These tendencies can make it harder for them to avoid cycling into other disordered emotional responses to trauma. On the upside, women tend to be more open about how they are feeling than men. In addition, they are more willing to seek out help when they realize they are struggling emotionally. Women also do better at creating support networks to help them sustain recovery after therapy has given them a healthy re-start. So while women are more vulnerable to developing PTSD, they are also more equipped to seek out and sustain recovery.