1 September 1939, which authorised his physician Karl Brandt and Reichsleiter Philipp Bouhler to begin the killing.

The killings took place from September 1939 until the end of World War II in Europe in 1945. Between 275,000 and 300,000 people were killed in psychiatric hospitals in Germany, Austria, occupied Poland, and the Protectorate of Bohemia and Moravia