MOSCOW (AP) _ Psychiatry was systematically used in the 1970s to suppress Soviet dissidents by declaring them mentally ill and committing them to asylums, a doctor wrote in the first article printed by state-run media to acknowledge such abuses.

''The leadership was content: in our country there were no dissidents - there were only insane people,'' Mikhail I. Buyanov, a psychiatrist and neurologist, wrote in his historical survey of Soviet psychiatry, published by the educational newspaper Uchitelskaya Gazeta.

Human rights activists in the Soviet Union and abroad have alleged for years that the Kremlin used psychiatric hospitals to incarcerate dissidents who were in fact mentally healthy. Some say the practice began under Josef V. Stalin or Nikita S. Khrushchev.

The government enacted a new law in January that makes it a crime to commit a sane person to a mental institution. But public health officials who have appeared at Moscow news conferences have denied that dissidents were systematically confined to asylums, or avoided answering the question.

However, Buyanov wrote that with the forcible confinement in 1970 of biologist and dissident writer Zhores Medevdev to a regional psychiatric hospital in Kaluga, ''a new chapter began in the history of Soviet psychiatry.''

''It's true that before this, people were sent to psychiatric hospitals for reasons that were mostly political, rather than of a medical character,'' Buyanov said. ''But after 1970, this was done more and more often.''

Medvedev, the brother of Marxist historian Roy Medvedev, was freed after human rights activist Andrei Sakharov, poet and editor Andrei Tvardovsky and others demanded his immediate release. He now lives in Britain.

Anatoly Koryagin, himself a psychiatrist, was sentenced to seven years in a prison camp in 1981 after accusing Soviet authorities of sending mentally healthy dissidents to hospitals, where they were forced to take drugs.

Those whose confinement Koryagin protested ''were expressing the same opinions, by the way, as were later heard from the tribune at the 27th Congress of the Soviet Communist Party and the 19th All-Union Party Conference,'' after Mikhail S. Gorbachev became Soviet leader in 1985, Buyanov wrote.

Koryagin was pardoned by parliament last year, freed from labor camp and emigrated to Switzerland. The government later stripped him of citizenship ''for causing damage to the prestige of the Soviet Union.''

Because of the abuses outlined by Koryagin, the United States and Britain considered trying to suspend or expel the Soviet Union from the World Psychiatry Association. The Soviets withdrew from the association in 1983, before a drive to expel them could be organized.

Buyanov gave no figures for the number of dissidents sent to mental hospitals, but said local party and police officials put pressure on psychiatrists to declare them insane.

Although the Ministry of Health instructed psychiatrists to ignore the opinions of non-professionals, ''Moscow was far away, and the local city party secretary was right next door,'' he wrote.

A definition of schizophrenia, a psychotic disorder, that was advanced by Soviet health specialists citing Marxist-Leninist doctrine also enabled psychiatrists to diagnose the ailment in sane people, Buyanov wrote in the article published by Uchitelskaya Gazeta on Saturday.

Under Leonid I. Brezhnev, Soviet leader from 1964 to 1982, psychiatrists gave law enforcement officials the notion that ''anyone who is against anything, it doesn't matter what, is a covert or overt mental case - more likely a psychopath or a latent schizophrenic,'' Buyanov said.

He praised measures taken earlier this year by the Health Ministry to improve the care of psychiatric patients, but said past abuses must be recognized. ''We have made mistakes. We have made them knowingly,'' he said.

Soviet psychiatrists also must be able to ignore pressure from authorities and threatening telephone calls and threats ''from above,'' Buyanov said.

In February, Modest M. Kabanov, a Leningrad psychiatrist, acknowledged at a news conference that some doctors in the past decided ''to send people to institutions for reading Bulgakov's works or for reading Pasternak's verses and poems.''

Works by the those two Soviet authors, Mikhail Bulgakov and Boris Pasternak, had been banned here until Gorbachev instituted his campaign for greater openness.

However, Kabanov and other doctors who appeared at the news conference skirted the question of whether psychiatry had been used in the Soviet Union to stifle dissent.