Gilbert Vila, a paediatrician who specialises in child trauma at Paris's Necker Hospital, said a child subjected to a deep shock of this kind was likely to show a long range of symptoms, including anxiety, depression, turbulence at school and problems in his family relationships.

"This case is of the gravest kind," he told AFP. "The psychological problems will be major."

Vila has authored several studies into the psychological impact on children who suffer a catastrophic shock, including a group of primary-school children taken hostage at their school in the Paris suburb of Neuilly in 1993.

Detailed research into Camb-odian children who were tortured under the Pol Pot regime and Armenian children who survived an earthquake shows that, for most victims, the big symptoms will gradually ease but for a minority the problems will be lifelong, Vila said.

In those cases, 90 percent of the children showed significant trauma symptoms during the first few weeks after their trauma.

That figure fell to 50 percent after six months, and to around 15 percent two or three years later. Some, though, were never completely cured.

In the Cambodian study, "some children who were aged between eight and 12 years at the time of their ordeal were still experiencing problems at the age of 30," he said.

More than half of the children in this category had problems that seriously hampered their daily life.

As for very young children and babies, "we still lack data" on the long-term repercussions, said Vila, noting however that there had been cases of children younger than four "who showed the same post-trauma symptoms as (US) Vietnam vets."