He often visited Western Europe and worked in the best clinics of Germany, Switzerland and France; he was fluent in many languages.

Pletnyov also clinically examined Soviet dictator Joseph Stalin and diagnosed him with "megalomania and a persecution complex" in 1937.

[1] In June 1937 Pravda published a slanderous article on Pletnyov "Professor-rapist, sadist" after which he was imprisoned in Lubyanka and sentenced to two years in prison on probation by a case fabricated by NKVD.

In December 1937, Dmitri Pletnyov was again arrested and in 1938 was a defendant on the process of the Anti-Soviet "Bloc of Rightists and Trotskyites", a show trial arranged by the NKVD.

[2] So he had to "admit" absurd charges such as having caused the death of Maxim Gorky by deliberately choosing "wrong methods of treatment" etc.