Chief Counselor
From USS Pacifica Online Database
Because of their training in psychology, technically the ship's/facility's Counselor is considered part of Starfleet medical. The Counselor is responsible both for advising the Commanding Officer in dealing with other people and races, and in helping crew members with personal, psychological, and emotional problems.
The Chief Counselor is considered a member of the Senior Staff. S/he is responsible for the crew in his/her department. The Chief Counselor is the Counselor with the highest rank and most experience.