GAZA CITY, Palestine: In a ward at Shifa, Gaza's largest hospital, child therapist Rabeea Hamouda is trying to elicit a response from two small brothers, Omar and Mohammad, aged three and 18 months, hoping for some words or perhaps a smile.
For seven straight minutes the children, peppered with burns and shrapnel wounds sustained in Israeli shelling that hit their home in north Gaza, stare at him blankly, emotionless.
Eventually, as Hamouda gently teases them, pretending to mix up their names and holding out a present while another counselor sings quietly, a smile creeps across Mohammed's face and the older one, Omar, cries out his name.
"At the beginning, Omar was not responding to us at all, he was not even willing to say his name," explains Hamouda, who heads a team of 150 psychotherapists working for the Palestinian Center for Democracy and Conflict Resolution in Gaza.
"Big progress has been made with these children," he says with a sense of relief and quiet accomplishment. "At the beginning they did not talk, they refused to communicate. But now, with the sixth session, we are witnessing good progress."
Omar and Mohammad are just two of the 400,000 Gazan children the United Nations estimates are in need of psychological care as a result of not just the latest war in the territory but the three previous conflicts fought with Israel since 2006.
The most recent conflagration has been the deadliest, with 1,945 Palestinians killed, many of them civilians and including an estimated 457 children. On the other side of the border, some 64 Israeli soldiers and three civilians have been killed.
Whether the result of Israeli airstrikes, having parents or relatives killed before their eyes, hearing militants firing rockets from their own towns or themselves being wounded, the psychological trauma for Gaza's young is profound.
The symptoms range from nightmares, bed-wetting and behavioral regression to more debilitating mental anxiety, including an inability to process or verbalize experiences.
There is also deep trauma on the other side of the border, with tens of thousands of Israeli children mentally disturbed by the regular rocket fire from militants during the monthlong war and over the seven years since Hamas seized control of Gaza.
While the conflict's destruction of buildings and livelihoods is clear to see and documented daily in television footage, the damage to minds is mostly invisible, yet can have far more damaging and longer-lasting consequences.
"The first time a child goes through a traumatic event like a war it's just deeply terrifying," said Chris Gunness, the spokesman of the United Nations Relief and Works Agency, which has 200 psychotherapists working in up to 90 clinics in Gaza.
"The second time is terrifying-plus-one because the child remembers the worst parts of the last war as well as the impact of the current one. Then the third time is plus-plus as the compounded memories of conflict build up.
"This time, for an 8- or 9-year-old child in Gaza, it's very, very intense indeed because there is this cumulative toll of trauma from repeated conflicts since 2006."
Hamouda and his team, like other psychotherapy units working across the small territory - home to an estimated 1.8 million people, more than half of whom are aged under 18 - can barely cope with the number of patients requiring help.
The treatment is by necessity basic - an effort to draw children out, to have them paint pictures of their experiences or emotions, to get them to verbalize their circumstances.
While a lot can be achieved with such simple techniques, many more require longer-term, personalized psychological care because of the enormity of the mental damage suffered.
"First we provide wounded and traumatized children with immediate pyscho-social support and we give parents some guidance on how to deal with them," Hamouda says. Then there is home care and follow up for the more severe cases.
"Houses can be rebuilt and some physical wounds can be healed, but the people's psychological condition needs more than money and time," he says. "It needs a big effort and persuasion, and overall it needs calm and stability."
One of Gaza's most successful trauma assistance projects is the Gaza Community Mental Health Program, launched in 1990.
Hassan Zyada, a psychologist with the project, describes the latest conflict as easily the worst since 2006, with scores of Palestinians having lost multiple family members.
"Our expectation is that more than 30 percent of the people here in Gaza will develop a psychiatric disorder," he said.
Even health professionals are not immune. Six members of Zyada's own family were killed during the war: his mother, three brothers, a sister-in-law and a nephew. He is now receiving counseling from the clinic's chief therapist.
"It is a really traumatic loss and it is not easy for me to deal with," he said, adding that several others on the team had suffered similar experiences.
So widespread has the psychological damage become that UNRWA, which runs schools throughout the Gaza Strip, has now made psychotherapy a regular part of the curriculum.
“We are rolling out a pretty massive program of parental and child therapy," Gunness said. "We're having to integrate this kind of therapy into our schools."