Twenty-five years after Hiroshima, the threat of the bomb is still very real, says Robert Jay Lifton, an expert on Nuclear Age psychology.

Lifton, professor of Psychiatry at Yale, is the author of Death in Life: Survivors of Hiroshima (1967), the definitive study of the victims of the first atomic blast.

He is particularly disturbed by "the kinds of attitudes our leadership has taken in the Vietnam war when the issue of nuclear weapons has arisen."

In an interview last week, Lifton listed a series of events that make "the present situation most immediate and most pressing." Among them are:

Then Vice President Richard Nixon's recommendation of the use of nuclear weapons in Southeast Asia in 1934-a suggestion vetoed by President Eisenhower.

South Vietnamese President Thieu's request for "sophisticated weapons" if and when American troops leave that country.

President Nixon's recent doctrine of "immediate and strong measures" when necessary "to save American lives."

All of this, said Lifton, is "justification for fear, concern and vigilance."

He added that he didn't "want at all to claim that nuclear warfare is inevitable-now or at any time."

Let Us Continue

In Death in Life, Lifton wrote that "our need is. . . to create new psychic and social forms to enable us to reclaim not only our technologies, but our very imaginations in the service of the continuity of life."

Now, three years later, he is "very unhappy with the lack of progress in that direction."

"By and large," Lifton said. "as a society we really haven't developed a more reasoned use of the bomb and nuclear weapons. We continue to lean on the bomb and build an illusion of security around it-when, in fact, its existence and the possession of the bomb is an increased danger for the possessor and for the rest of the world."

Lifton has "never had much faith" in nuclear deterrents.

"They are not a reliable balance of equilibrium," he said. "They are based on technological and human factors that are inherently unstable. This constant building of weapon upon weapon creates a kind of dynamic that's always dangerous to have, because it can so easily imbalance."

While Lifton feels his lengthy research on this issue has sensitized him to the whole problem, he feels that the public at large is now less concerned with the bomb.

Dubious Achievement