Communist orthodoxy banished Freud for Pavlovian behaviorism after 1923

Evidence

In the 1970’s it is difficult to appreciate the audacity of the first theorists who proposed the unnatural marriage of Freud and Marx. With the recent resurgence of interest in Wilhelm Reich and the widespread impact of Marcuse’s Eros and Civilization, the notion that both men were speaking to similar questions, if from very different vantage points, has gained credence among many on the left. A generation ago, however, the absurdity of such an idea was rarely disputed on either side of the Atlantic. Although Trotsky had been sympathetic to psychoanalysis, his voice was no longer heard in orthodox Communist circles after 1923, when a taboo descended on Freud and his followers and Pavlovian behaviorism became the new orthodoxy. — Martin Jay, The Dialectical Imagination, 315

Categorization

• QUESTION: What exactly triggered the taboo on psychoanalysis in Communist circles in 1923, and how did Pavlovian behaviorism become the formal orthodoxy?