The benefits of psychologial debriefings are apparent even in people who are unlikely to develop post-traumatic stress disorder (PTSD), says the research.

Turning to alcohol is a well documented reaction in people who have witnessed a traumatic event.

It can be used as an emotional crutch as they struggle to come to terms with what they have seen.

Tour of duty

Dr Martin Deahl, a psychiatrist at St Bartholomew's Hospital in London, led the research which studied 106 British soldiers after they returned from six months of peacekeeping duties in Bosnia.

During that time they were fired upon and saw civilians being attacked.

The soldiers were split into two groups at random, and, following general health checks, one group received psychological debriefings while the other did not.

The debriefings consisted of talking through the events they had witnessed with professional counsellors.

Both groups had follow-up interviews at three, six and 12 months to check on their mental state.

Surprise finding

The researchers wanted to see if psychological debriefings could prevent PTSD.

The condition can occur after a severely disturbing event such as being raped or robbed, or after exposure to a highly stressful environment, such as a war zone.

Psychological debriefing is often offered to prevent the condition in soldiers after a tour of duty or in bank employees after an armed raid.

The army allows active soldiers two beers a day in Bosnia

Dr Deahl reported last year that in some circumstances the practice could do more harm than good.

In the new study he found that it had no significant impact on incidence of the disorder - one soldier in the debriefed group and two in the other suffered it - but it halved the number of men reporting alcohol problems after one year.

The findings are soon to be published in the British Journal of Medical Psychology and are reported in New Scientist magazine.

Overlooked symptoms

"It suggests that the debriefing is having a beneficial effect after all, but that we haven't been looking at the right things," Dr Deahl told BBC News Online.

"Sometimes with people with PTSD their social and occupational functioning breaks down and they start drinking or using drugs."

He said that the low incidence of classic PTSD in the soldiers returning from Bosnia was a surprise in itself.

"It shows that being in conflict, being shot at and being bombed, it isn't inevitable that you're going to get PTSD."

Preparation

Dr Deahl, himself a member of the Territorial Army, said this was thanks to the way in which the Army prepared soldiers for traumatic situations.

"These soldiers had an occupational stress training package, which prepares them for the kind of experience they're going to have on operational tours," he said.

He added that alcohol education could be included in such pre-briefings.

"Developing more packages like that would help, and also more alcohol education. Now, for example, in Bosnia they have a limit so they're not allowed to drink more than two cans a day anyway."