Medical School professors yesterday began a conference, sponsored jointly with the Harvard-affiliated Cambridge City Hospital, to inform doctors about the biological and psychiatric dangers posed by the looming threat of nuclear war.

More than 200 physicians and psychiatrists from around New England attended the conference, which ends today, and listened to professors from Harvard. MIT, Johns Hopkins University and Yale discuss issues including the ethical problems doctors would face in the event of a nuclear war.

The conference is designed to help physicians "understand and confront" the "fear and suspicion" which has led policy makers--in both the U.S. and the Soviet Union--to make "irrational decisions" which have accelerated the arms race, said John E. Mack, professor of Psychiatry at eh Cambridge City Hospital, and conference organizer.

In his opening remarks. Mack linked the rise of apocalyptic religions, the transience of modern society, as well as Americans' and Soviets' widespread drug and alcohol abuse to failure to cope with the fear of living the nuclear age.

Several speakers at the Park Plaza Hotel referred to the increasing number of children who have recurring nightmares of nuclear destruction and the growing "preoccupation with this threat among adolescents."

Anti-nuclear activist Dr. Helen M. Caldicott, former clinical instructor in Pediatrics at the Harvard-affiliated Children's Hospital, said the World War II decision to launch a nuclear attack against

The Medical School plans to offer its first course on the nature and effects of nuclear war next semester because doctors must play a key role in leading protests against the escalating nuclear arms race, four organizers of the new program said yesterday.

"This course is a sign of the growing awareness that we are facing the final epidemic--nuclear war." James E. Muller, assistant professor of Medicine, said, adding that to prevent such an epidemic, physicians must fill a "special role."

The Medical School's committee on curriculum has not yet formally okayed the course, but Alexander Leaf. Jackson Professor of Clinical Medicine, said yesterday that official approval will likely be granted at the committee's December 7 meeting.