For Shmuel Mikulincer, the Holocaust is not a chapter in some history book or a pile of papers in a dusty archive. It's an experience he carries with him every day.

Born in Czechoslovakia in 1921, he spent much of the second World War on the run from the Nazis. At times he masqueraded as a non-Jew; at times he hid in forests, in the snow; and on one occasion he covered himself in earth in order to evade capture. Mikulincer's family was less fortunate. His parents, three of his sisters and a brother all perished at the Auschwitz death camp in German-occupied Poland.

Fifty-five years on, the traumas of the Holocaust have not vanished for Mikulincer, who now lives in Israel. "Many times I've had difficulty falling asleep at night", he says. "I've had thoughts about my parents, my brother, my sisters. The terrible things that I saw. The incredible cruelty."

While the traumas of the Holocaust - the trains, the concentration camps, the mass executions - live on in the memory of all of the 300,000 survivors now living in Israel, some 700 to 800 of these people are suffering chronic mental disorders, such as schizophrenia, and have been hospitalised for more than 50 years.

Beyond the serious cases of mental illness, there are several thousand survivors who suffer from posttraumatic stress and who may experience bouts of anxiety as a result of everyday associations which remind them of life in the concentration camps or on the run from the Nazis. Something as seemingly innocuous as a passing train or a barking dog may trigger Holocaust associations.

"For Holocaust survivors, present-day experiences spark frequent associations with the past", says Dr Natan Kellermann, the chief psychologist at the Jerusalem branch of Amcha, an organisation offering psycho-social support to survivors and their children. "For survivors", he says, "the Holocaust is ever-present."

The anxiety, says Dr Kellermann, can manifest itself in different ways; in the form of sleeplessness or loss of appetite, for instance. One frequent problem experienced by survivors is nightmares. "They may wake up at night screaming", says Dr Kellerman. "But if you saw that person during the day, they would appear completely normal to you."

Dr Kellermann recently treated an elderly couple who had been suffering from a bout of flu, were unable to sleep and had lost their appetite. "Because of their state of physical weakness", he says, "their feeling of vulnerability from the Holocaust was being reactivated. Their bodies were reacting unconsciously to this."

Dr Kellermann believes that it is still too early to determine whether the release of the memoirs and notes of Adolf Eichmann will have any psychological impact on survivors. "I imagine", he says, "that this information might be of significant interest to people who were in the camps. I'm sure it will bring back memories. And they will certainly curse him when discussing the issue."

It was the Eichmann trial in 1961 which shattered the silence of the survivors, many of whom had been ashamed to speak of their horrific experiences. "For the first time", says Dr Kellermann, "people began to listen to the survivors. They became heroes, not just victims."

The majority of survivors in Israel today have rebuilt their lives and function tremendously well, he says. "Yet", he emphasises, "for every survivor, the Holocaust is a constant part of their inner lives".