June 3 (HealthDay News) -- Having recent trauma survivors relive the troubling event in a controlled environment may help prevent them from developing post-traumatic stress disorder (PTSD), according to a new report.

This exposure-based therapy approach is not new, but clinicians sometime avoid using it under the belief it distresses the survivors too much, according to background information for the report, published in the June issue of Archives of General Psychiatry. Instead, they tend to favor cognitive restructuring, which focuses on changing thoughts and responses to a traumatic event.

In an Australian study, 90 patients who developed acute stress disorder after a non-sexual assault or motor vehicle crash were randomly assigned to five weekly 90-minute sessions of exposure therapy or cognitive restructuring, or they were wait-listed for treatment.

After completing treatment, fewer patients who received exposure therapy met criteria for PTSD than those in the cognitive restructuring group (33 percent vs. 63 percent) or the wait-list group (77 percent). The ratio for exposure therapy versus cognitive restructuring held fairly closely in a follow-up exam done six months later; however, 47 percent of the patients getting exposure therapy had achieved full remission, while only 13 percent of those in the cognitive restructuring group did.

Despite some concerns that patients may not be able to manage the distress elicited by prolonged exposure, there was no difference in drop-out rates for the prolonged exposure and cognitive restructuring groups (17 percent vs. 23 percent), the authors wrote. In addition, by the end of three sessions, the distress ratings were significantly lower in the exposure therapy group than in the cognitive restructuring group.

Exposure therapy may be more effective than cognitive restructuring, because it eases the anxiety associated with the traumatic memory and corrects the belief that the memory must be avoided, in addition to encouraging self-control, the authors noted.

The current findings suggest that direct activation of trauma memories is particularly useful for prevention of PTSD symptoms in patients with acute stress disorder, the authors concluded. Exposure should be used in early intervention for people who are at high risk for developing PTSD.

SOURCE: Journal of the American Medical Association, news release, June 2, 2008