A psychiatric subroutine was a program that enabled an EMH to serve as a psychiatrist. In 2374, The Doctor was in the process of developing a psychiatric subroutine to add to his program, as USS Voyager was lacking a ship's counselor. He hoped to become even more valuable to the crew by doing so. He mentioned this to Kathryn Janeway when she expressed her surprise upon his planning to use a therapeutic regression technique on Seven of Nine, as she was unaware that he could practice that field of medicine. (VOY: "Retrospect")