Dr. M. Prentiss Bailey, 86, a government psychiatrist for 50 years who once studied in Vienna under Sigmund Freud, died of pneumonia Jan. 11 at the Veterans Administration Hospital in Martinsburg, W.Va.

Dr. Bailey was born in Charleston S.C., and reared in Washington. He earned a bachelor's degree at George Washington University and was a 1917 graduate of the Hahnemann Medical College in Philadelphia.

After postgraduate training at the University of Vienna, where he studied under Freud, he returned to this country and joined the U.S. Public Heath Service. He became a Veterans Administration psychiatrist in the early 1920s.

Dr. Bailey served in the Army during World War II and attained the rank of colonel. During much of this time he was chief of the neuropsychiatric service at the Veterans Administration facility at Montgomery, Ala.

After the war he was a senior psychiatrist at Veterans Administration hospitals in the South, Midwest, and on the West Coast before returning to Washington in the 1950s.

Following his retirement in 1965, Dr. Bailey continued his work as a specialist in neuropsychiatry while serving as a consultant to the Veterans Administration Hospital in Washington. He retired a second time in 1970.

He was a diplomate of the American Board of Psychiatry and Neurology and was a member of both the American Medical Association and the Fifty Year Club of American Medicine.

Dr. Bailey maintained a lifelong interest in the dramatic arts. In his youth, he appeared in a Broadway production of "Hamlet" after earning a diploma at the American Academy of Dramatic Arts in New York.

He has resided in the District of Columbia for the past 25 years.

He is survived by his wife of 40 years, the former Edilesa Maria Von Brockmeyer, of Washington.