ALEXEI NIKITIN, 41, is a mining engineer in the Soviet Ukrainian city of Donetsk who, 10 years ago, fell afoul of the authorities for taking up the cause of workers who had been cheated of their wages and forced to work in unsafe mines.He was punished with a 10-year regime of prisons and police-run psychiatric hospitals. Released, he nonetheless sought out Western journalists to introduce them to life in his city. It was on the basis of information amd contacts he provided that this newspaper's Moscow correspondent, Kevin Klose, wrote a series of articles recently on the atrocious conditions that common workers and pensioners know in Donetsk.

Four days after Mr. Nikitin received the press, he was arrested. It is now reported that he has been sent to the police-run Dniepropetrovsk Special Psychiatric Hospital. It is his second tour. In an earlier four-year stay, he had been pronounced "psychopathological -- simple form" by a panel that included a man who took off his doctor's outfit at the end of each session to reveal a KGB colonel's uniform underneath. He had been confined to a 26-by-20 room with 30 wretched men. He had been injected with sulphazin, which felt "like a drill boring into your body that gets worse and worse until it's more than you can stand -- it's impossible to endure," he told Mr. Klose in Donetsk.

At this point late in the 20th century it is no surprise to find the Soviet government brutalizing an honest person, a member of the Communist Party but one who has been trying to help his fellow workers win some of the rights and benefits theoretically (key word) guaranteed by their country's laws and constitution. The surprise is perhaps that there are still individuals brave enough to make the kind of statement Mr. Nikitin has been making for the last 10 years.

But what can be said of a government that, not for the first time, perverts the instruments of healing into tools to destroy a healthy man? It begins to look, moreover, as though the KGB allowed Mr. Nikitin his Western press contacts in order to set up a reprisal meant to be doubly intimidating: to wreak venegeance on him in full public view. If that is the case, the KGB should know, as should Mr. Nikitin, that nothing more effectively confirms the dark picture of Soviet life he drew than the KGB's punishment of him for drawing it. His courage and his government's depravity stand at opposite extremes.