ANN ARBOR—Once thought to be a rare condition except among combat veterans and civilians unlucky enough to be involved in natural disasters, post-traumatic stress disorder (PTSD) is surprisingly prevalent among U.S. adults, especially women, according to a University of Michigan study to be published in the December issue of the Archives of General Psychiatry.

Nearly 8 percent of all Americans between the ages of 15 and 54 experienced an episode of post-traumatic stress disorder at some time in their lives, according to U-M sociologist Ronald C. Kessler, the principal investigator of the study, based on the first survey to administer in-person psychiatric interviews to a national sample of the general population.

“Women are twice as likely as men to suffer from PTSD,” says Kessler, a senior researcher at the U-M Institute for Social Research. “The lifetime prevalence of the disorder is 10.4 percent for women compared to 5 percent for men. And for fully half the women who suffered PTSD, the trauma most closely linked to the onset of the disorder was either rape or sexual molestation.”

PTSD is often a chronic condition, Kessler notes, with over one-third of people still suffering from the disorder a decade after the trauma occurred.

To be diagnosed as suffering from PTSD, respondents had to report exposure to at least one traumatic event, including rape, sexual molestation, physical attack, combat, physical abuse, natural disasters, or being a witness to the death or physical abuse of another. Respondents also had to report such symptoms as reliving their experience in nightmares, or having flashbacks or intrusive thoughts, or developing emotional numbness, avoidance, or hypersensitivity for periods of a month or more.

Sixty percent of men and 51 percent of women in the general population reported experiencing at least one traumatic event at some time in their lives. The three most common events were as follows: witnessing someone being badly injured or killed (35.6 percent of men and 14.5 percent of women), being involved in a fire, flood or natural disaster (18.9 percent of men and 15.2 percent of women,) and being involved in a life-threatening accident (25 percent of men and 13.8 percent of women).

A significantly higher proportion of men than women reported experiencing each of these three traumatic events, as well as physical attacks, combat, and being threatened with a weapon, held captive or kidnapped. A significantly higher proportion of women, however, reported being raped, sexually molested or subjected to parental neglect and physical abuse during their childhoods.

Although men were more likely than women to experience at least one trauma overall, women were more likely than men to develop PTSD. In fact, Kessler and colleagues report, women exposed to a trauma are more than twice as likely as men to develop PTSD” 20.4 percent vs. 8.2 percent.

“We do not entirely understand why this difference exists,” says Kessler, “but at least two factors are involved. First, women are more likely than men to experience the kinds of highly traumatic events—rape and sexual abuse in particular—that are most likely to lead to PTSD. Second, it is possible that women are more emotionally reactive than men are to certain kinds of trauma due to as-yet undetermined vulnerability factors.”

The National Comorbidity Survey, upon which the study was based, was funded by the National Institute of Mental Health, the National Institute of Drug Abuse, the W.T. Grant Foundation, and the John D. and Catherine T. MacArthur Foundation.

Kessler’s co-authors are Amanda Sonnega and Christopher Nelson of the U-M Institute for Social Research; Evelyn Bromet of the State University of New York, Stony Brook; and Michael Hughes of Virginia Polytechnic Institute and State University.

EDITORS: The following are the names and numbers of additional experts familiar with this study, who have agreed to discuss the study’s findings and implications:

Naomi Breslau, Director of Research, Department of Psychiatry, Henry Ford Health Sciences Center, Detroit, MI, (313) 876-2516;

Jonathan Davidson, Professor and Director, Anxiety and Traumatic Stress Program, Duke University Medical Center, Durham, NC, (919) 684-2880;

Susan Solomon, National Institutes of Health, Rockville, MD, (301) 496-0979.

National Institute of Drug AbuseJohn D. and Catherine T. MacArthur Foundation