Survivor's guilt

Survivor's guilt was the psychological condition resulting in the feeling that a person had done wrong by surviving traumatic events, such as combat or disaster. The effect of survivor's guilt depended on the individual person's own psychology.

Apparent sufferers included Bernice Summerfield, (PROSE: Love and War) and the Ninth, (TV: Dalek) Tenth, (TV: Gridlock, The Day of the Doctor) Eleventh (TV: The Time of the Doctor) and Twelfth Doctors. (TV: Before the Flood, The Zygon Inversion) A Time Lord author noted that the War Doctor's successors kept their guilt at bay by insisting to themselves that their warrior self's actions had been worth it. (PROSE: A Brief History of Time Lords)

Ironically, the Eighth Doctor had insisted he was psychologically incapable of such a thing after Marnal insisted he had survivor's guilt due to the Time Lords being wiped out during the War. (PROSE: The Gallifrey Chronicles)

The Doctor began to move on from their feelings of guilt as they kept regenerating, but the psychological scarring of what they remembered doing to end the Last Great Time War still dwelt within them. (TV: School Reunion, Doomsday, Gridlock, The Sound of Drums, The Doctor's Daughter, The Beast Below, The Hungry Earth, The Doctor's Wife, Death of the Doctor, The Zygon Inversion, PROSE: The Day of the Doctor) The Twelfth Doctor used this guilt as a driving force to make sure no one else would ever have to feel how he did. (TV: The Zygon Inversion)