May 9 (HealthDay News) -- Breast cancer patients are more than twice as likely to develop post-traumatic stress disorder if they have had previous mood and anxiety disorders, new research suggests.

About 16 percent of the 74 breast cancer patients studied by researchers at the Ohio State University Medical experienced PTSD 18 months after their cancer diagnosis. These same patients were three times more likely to have had anxiety disorders.

"What is unique about breast cancer patients with PTSD is that they have already had this double hit of both anxiety and mood disorders even before they got the diagnosis," study co-author Barbara Andersen, a professor of psychology at Ohio State University, said in a prepared statement. "So when they are in a new situation that is very anxiety-provoking -- cancer diagnosis and treatment -- it is not surprising that they are at risk for developing PTSD."

While the study suggests most cancer patients aren't at risk for post-traumatic stress disorder, Andersen said mood disorders are a concern.

"I think depression is the mental health condition that needs the most attention as far as treating breast cancer patients, even more so than PTSD," she said. "That's the direction our research is going, and we are working to develop an intervention to treat cancer patients with depression."

She said the findings, published in the April issue of the Journal of Traumatic Stress, suggest screening newly diagnosed breast cancer patients for past mood disorders might help avoid their developing post-traumatic stress disorder.

Another 20 percent of those in the study had "subsyndromal" post-traumatic stress disorder, a condition in which they experienced significant symptoms of PTSD but not at the level of those with the full diagnosis.

About one-third of women with PTSD also had past problems with alcohol/substance abuse or dependence, compared to one-fifth of subsyndromal women and one-tenth of women with no PTSD.

Also, patients who developed PTSD tended to have a history of traumatic life events, the study reported. Half of the PTSD patients reported being physically attacked or abused previously, compared with less than 17 percent of the other women.

SOURCE: Ohio State University, news release, May 5, 2008