Between 1939 and 1945, 180,000 psychiatric patients were killed in Nazi Germany. This paper opens with a brief discussion of the reasons for addressing this issue today; it is followed by the details of the so-called euthanasia program that entailed killing of patients by gas in special hospitals in the years 1939-1941, and in psychiatric hospitals in the years 1942-1945. In this latter period, patients were killed with lethal injections and through the introduction of a starvation diet. The fate of the Jewish patients and forced laborers, as well as the experiments conducted on the patients, are mentioned. Finally, some thoughts are presented to answer the question of why this could have happened. To me, the giving up of individual responsibility in an authoritarian system leads to the loss of the individual conscience and soul, including those of a psychiatrist.