The natural "survival instinct" in soldiers enables them to concentrate on their fighting, even with little sleep or food - but accidentally killing comrades may be psychologically devastating for a long period, according to a Jerusalem clinical psychologist who has worked with demobilized soldiers suffering from trauma. Some 20 soldiers wounded in errant tank shelling on Monday remain hospitalized at several hospitals around the country. One is still in critical condition, three in serious condition, while the others sustained light to moderate wounds. Dr. Danny Brom, director of the Temmy and Albert Latner Israel Center for Treatment of Psychotrauma (ICTP) at Jerusalem's Herzog Hospital, told The Jerusalem Post in an interview that soldiers who were not previously in action can be nervous and fearful, but this can be reduced when the line of command is clear and strong and the commander is trusted. A psychological breakdown is uncommon during battle, Brom said, but when it does occur, it is almost always long after battle, developing into post-traumatic stress disorder or other problems, especially when not treated. Survival mode makes the soldier very alert and able to carry out tasks much quicker, Brom said. But being involved in tragic "friendly fire" incidents, as the two that occurred and killed four soldiers on Monday night, can be very painful and arouse intense guilt among those soldiers involved, he added. Brom and his colleague Dr. Ruth Pat-Horenczyk (director of child and adolescent services at the psychotrauma center) have developed a model - based on short-term group therapy combined with outdoor adventure therapy - that offers hope for relief of emotional trauma in demobilized soldiers. Called Peace of Mind, the pilot project is supported by foreign donors, with the enthusiastic cooperation of IDF units that have participated so far. It was launched by the center after the Second Lebanon War. Retreats for a small number of soldiers from elite units participated in week-long foreign trips during which they participated in two daily psychotherapy sessions for reviewing what they had gone through and coming to terms with it, along with touring and relaxation. It proved to build resilience and relieve trauma, Brom said. Another group will soon follow. Fighting for the first time is like childbirth, he acknowledged. As you have never done it for real before, you are naturally anxious. But having been through it and having been exposed to traumatic events before can either ease the experience or make it more difficult. Yet, he said, the IDF has ways to bolster motivation and the inborn survival instinct, as well as minimizing fear and anxiety.