On 22 June 1941, the German army invaded the Soviet Union. At least 17,000 psychiatric patients also fell victim to the war of annihilation against the Soviet population.

SS-Einsatzkommandos (task forces) murdered thousands of psychiatric patients in Ukraine in the autumn of 1941. For example, 1,500 patients in Vinnitsa were shot and poisoned so that the institution might be used as a sanatorium for the Wehrmacht. In Belarus, the head of Einsatzgruppe B, Arthur Nebe (1894–1945), tested, together with the chemist Albert Widmann (1912–1986) from the Reich Security Main Office in Minsk and Mogilev, »effective« forms of murder. In a forest near Minsk, they tried to kill psychiatric patients by means of explosive devices. A provisional gas chamber was set up in the Psychiatric Hospital Mogilev. In Southern Russia Einsatzgruppe D also murdered 214 children in a home in Yeisk using a gas van.