Three years ago Dr. Marina Voikhanskaya, 43, a handsome, dark-haired psychiatrist, left her home in the Soviet Union forever. Her spiritual exile had begun two years before, when she visited a dissident artist, Yury Ivanov, a patient in the Leningrad hospital where she worked. "After looking through his case history and talking to him," she recalls, "I realized that a perfectly sane man was being confined with psychotic patients and no one cared. I wanted to run out into the street and scream, 'People, where are you?' "

Soon thereafter, the Soviet KGB asked Dr. Voikhanskaya to pronounce another patient, the poet Anatoly Ponoryev, insane. She refused. "You can't imagine how scared I was when I wrote my opinion," she says. "I cried for two hours before I signed because I knew my life would go to pieces." Harassed by the KGB, transferred to the geriatric ward and threatened with dismissal, the doctor applied for a visa to emigrate. She flew to Vienna, then on to London, where she expected her 9-year-old son, Misha, to join her. Her ex-husband, a military engineer, had promised he would send the boy to her, says Marina, and, perhaps naively, she believed him.

Once Dr. Voikhanskaya was out of the country, however, the Soviets began turning the screws. Misha's father—under pressure from the KGB, she maintains—refused him permission to leave for the West. Marina, who is Jewish, believes the action was taken in retaliation for her outspoken denunciation of Soviet human rights violations. Last summer, at a stormy meeting of the World Psychiatric Association in Honolulu, she characterized the hospitalization of dissidents as "a crime that has nothing to do with psychiatry"—a charge the Soviet press labeled "slanderous."

Since then Dr. Voikhanskaya, who acknowledges that the price of Misha's freedom may be her own silence, has stubbornly refused to back down. No halfway recantation, she knows, will suffice. "With the Soviet government," she explains, "if you say A, you must also say Z. You can't stop in the middle. Otherwise, you'll be considered weak and stupid." Her dilemma is agonizing. "Maybe I sound fanatical," she says, almost apologetically, "but my patients are my children too. How can I look into Misha's eyes if I'm not honest? Even he says I was right."

Misha, now 12, can, in fact, be quite as resolute as his mother. Living with his widowed grandmother in a small flat in Leningrad, he recently wrote to Soviet Premier Leonid Brezhnev, pleading for his freedom. The letter went unanswered, and in December the boy was beaten up for the second time by a bunch of teenage boys, who called him a "Jewish pig." When he complained to his teacher, she told him it was his imagination. Misha went on a hunger strike. Four days later the boys apologized. Though Misha's father does not visit his son, the government has threatened to strip Dr. Voikhanskaya of maternal rights, condemning her never to see Misha again.

Now visiting friends and taking medical courses in New Jersey, the doctor makes her home in London, where she is preparing for her license to practice in Britain. She writes to Misha almost daily to lift herself from bleakest depression. "In a way I feel I'm a criminal," she admits. "I feel guilty because I left my son. For me it would be easier to be imprisoned in a mental hospital in Russia—and that is what they were going to do to me—than to stay in the West without Misha." She has already gathered 3,000 signatures on a petition for the boy's release, and a "Let Misha Go" Committee was formed recently in London with playwright Tom Stoppard as honorary president. Saul Bellow, Arthur Miller and Joan Baez are members. Voikhanskaya has also appealed to the U.S. State Department for help.

Whatever her regrets about the course she has taken, there is no turning back. "If I returned now," she says solemnly, "I'd have to earn my way. That is, I'd have to betray everyone and everything. I'd have to say I was CIA. Even for Misha, I can't do that."