Freud was preoccupied with thoughts of death and dying from early childhood to old age. As in the life of many great men, mortality and immortality were driving motives in his work and achievement. It is possible that his theory of the death instinct grew out of this conflict about the acceptance of human fate and acceptance of death as a part of reality. It is also possible, or at least within the field of imagination, that it is this type of personality who always lives in or near the awareness of death (which includes a constant guilt about murderous hostility) who may finally develop cancer.

Freud's cancer is more a symbol, a sign, a mark of death, than that it prompted him to write about death instincts. The development may have proceeded from preoccupation with death to scientific elaboration and perhaps to psychosomatization in the form of a cancerous growth.

Freud faced death directly and courageously. He expressed that once when he said: “I think of death every day. This is a good training.”