Western governments should press the Soviet Union to respond to President Carter's human rights declaration while they continue to open up trade relations. Leonid Plyushch, a Ukrainian mathematician and Soviet dissident, told an overflow crowd at Boylston Hall Auditorium last night.

"The opportunity for a political, economic and social coming-together, without adherence to human rights, is worth nothing," he said through an interpreter.

Plyushch, who was arrested and confined to a Soviet mental institution in 1973, was scheduled to speak on "Psychiatry as a Tool of Soviet Political Oppression." He confined most of his remarks, however, to a discussion of the efforts of Soviet dissident groups to pressure their government to adhere to the human rights provisions of the 1975 Helsinki Accord.

Plyushch added that the present Soviet government is actually a conservative state-capitalist system. "Stalin, having destroyed all his ideological opponents, destroyed socialism," he said.