The authors reviewed 290 studies conducted between 1980 and 2005 to determine who is more at risk for potentially traumatic events (PTE) and posttraumatic stress disorder (PTSD) ? males or females? The results of the meta-analysis found that while males have a higher risk for traumatic events, women suffer from higher PTSD rates. PTSD is defined as an anxiety disorder precipitated by a traumatic event and characterized by symptoms of re-experiencing the trauma, avoidance and numbing and hyperarousal.

From the review, researchers David F. Tolin, PhD of the Institute of Living and Edna B. Foa, PhD, of the University of Pennsylvania School of Medicine found that female study participants were more likely than male study participants to have experienced sexual assault and child sexual abuse, but less likely to have experienced accidents, nonsexual assaults, witness death or injury, disaster or fire and combat or war. Sexual trauma, the authors conclude, may cause more emotional suffering and are more likely to contribute to a PTSD diagnosis than other types of trauma.

Women's higher PTSD rates were not solely attributable to their higher risk for adult sexual assault and child sexual abuse, explained Tolin. PTSD rates were still higher for women even when both sexes were compared on the same type of trauma.

"PTSD may be diagnosed more in women in part because of the criteria used to define it. Cognitive and emotional responses to traumatic events make a diagnosis of PTSD more likely. So even though men may experience more traumas, they don't seem to have the same emotional responses to traumatic events," said Tolin and Foa.

Furthermore, according to the authors, those participants who experienced multiple traumas may be more vulnerable to re-experiencing old PTSD symptoms when confronted with a new trauma. For example, if one studies male and female survivors of a motor vehicle accident, typically the female accident victims report more PTSD symptoms than do the male accident victims. "However, the data suggest that the female victims will have brought to the table a much greater risk of abuse and sexual assault prior to the accident; this could place them at higher risk of developing PTSD after the accident even though the current accident may not have caused all the symptoms," said Tolin.

These findings were consistent regardless of the population and age examined and the type of study and assessment tool used.

A reason that men may not fit the current diagnosable criteria of PTSD, said Tolin, is that their symptoms may manifest themselves differently. The male participants examined in this review were less likely to report anxiety or depression, but were more likely to report behavior and drug problems. They were also more likely to become irritable, angry or violent after traumas.

Understanding that responses to trauma can vary from person to person will help better determine if a person has experienced a trauma, said Tolin. An example of how subjective trauma symptoms can be illustrated in research investigating the traumatic effects of 9/11 terrorist attacks. Quite a few studies showed that participants' distance from ground zero was directly related to the likelihood of experiencing severe PTSD symptoms. But, said Tolin, "People from all over the U.S. could technically have been classified in research as having 'experienced' a terrorist attack just by watching it on TV. This is a major problem for trauma research because it's hard to determine whether someone has really been traumatized or not."

"Simple checklists or short interviews are insufficient for assessing trauma and this is what is used most in these types of situations. More thorough assessments are needed to know if someone will suffer long-lasting symptoms from an accident, attack or disaster," said the authors.