An initial clinical trial conducted on 24 people involved in traffic accidents seems to corroborate earlier animal experiments indicating that it may be possible to develop a "morning-after pill" to prevent the development of post-traumatic stress disorder. The Israeli researchers who conducted the trial determined that the administration of a hormone reduces the risk of developing PTSD by 80 percent.

The project, led by Prof. Joseph Zohar, head of the psychiatry department at Sheba Medical Center, Tel Hashomer, and chairman of the Israeli Consortium on PTSD, is designed to develop a treatment to prevent psychiatric episodes, similar to the treatments administered today after a stroke to prevent further complications, or after an event that could lead to post-traumatic stress disorder.

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"Most psychiatric conditions, such as depression or even schizophrenia, develop gradually and not at a specific point in time, but PTSD appears in response to a specific traumatic event," explains Zohar.

"The treatment of post-trauma in the past several years is rich in myth and thin on facts, especially when it comes to first-aid after exposure to trauma," he adds.

Until recently, it was common practice to treat individuals exposed to traumatic events with tranquilizers from the Benzodiazepine family, such as Valium. But apart from their relaxing effect, these drugs delay the release of cortisol in the body. Animal experiments suggest that this "neutralization" of the hormone reduces the body's ability to defend itself against PTSD. American medical organizations began advising against Benzodiazepine treatment directly after stress exposure, and researchers began looking for better pharmaceutical alternatives.

Prof. Hagit Cohen, head of the anxiety and stress research unit of Be'er Sheva's Ben-Gurion University of the Negev, carried out an animal trial in which mice were exposed to a stress stimulus - in this case, litter soaked in cat urine. Some of the mice developed extreme stress symptoms, which were reduced when they were injected with cortisol shortly after developing the symptoms. The results of the study were published in the Biological Psychiatry journal in 2008, and gave rise to the human trial.

The pilot involved 24 survivors of traffic accidents who showed symptoms of stress after being admitted for treatment at the Sheba emergency room. Of the 12 subjects who were treated with the one-time injection of cortisol, only one was diagnosed with PTSD a month after the exposure to stress; at the end of a three-month period in which their conditions were monitored, none showed signs of PTSD. Of the 12 who received a placebo injection only, three developed PTSD.

The accepted medical definition of PTSD is the presence of an acute stress reaction to exposure to a traumatic event for at least a month after the event itself. Between 10-15 out of every 100 individuals are likely to develop PTSD after exposure to traumatic events; among people considered at high risk, who present with stress symptoms shortly after the exposure, as in the case of the Sheba trial subjects, the risk of PTSD climbs beyond 50 percent.

In the trial, 100 milligrams of cortisol were administered by injection, but Zohar noted that the use of cortisol in pill form will also be examined. Cortisol has a number of medical uses, and in the case of allergic and asthmatic attacks, it is administered in larger doses than the ones used in the clinical trial.

The protocol for the trial called for administering the cortisol within six hours after the exposure to the traumatic event - in this case, a traffic accident.

"In medicine, we call this period 'the golden hour' - in this case, the period during which the traumatic memory is fixed. If the emotional memory is not fixed in place, PTSD does not develop later on," Zohar said.

The results of the trial will be published in the December issue of the European Neuropsychopharmacology journal. The researchers recently received approval in principle for a research grant from the U.S. National Institute of Mental Health.

The results of the clinical trial could pave the way for the development of preventive treatments in psychiatry, similar to the administration of tetanus vaccine after exposure to toxins.

"The work raises the possibility in the future of developing a rapid treatment that could be given to people, such as combat soldiers, who have been exposed to traumatic events. There is a need for an agent that could be administered in the field and that does not impair motor responses or performance and that does not have a soporific effect - and cortisone meets these requirements," Zohar said.