Dr. John A. Farrell, 74, a psychiatrist in the Washington area for more than 40 years until he retired in 1983, died Oct. 6 of pneumonia at George Washington University Hospital.

Dr. Farrell, the brother of the late novelist James T. Farrell who died in 1979, was born in Chicago, attended Loyola University and the University of Chicago and received his medical degree from Northwestern University. He came to Washington in 1942 as medical officer at St. Elizabeths Hospital, and he remained at St. Elizabeths until 1946 when he entered private practice of psychiatry.

Dr. Farrell remained in private practice in Washington and in Silver Spring until 1975 when he returned to St. Elizabeths as medical officer. He remained there until he retired.

A resident of Silver Spring, Dr. Farrell was a former assistant clinical professor in the department of psychiatry and behavioral sciences at George Washington University medical school. He was a D.C. police and fire department psychiatrist from 1966 to 1975 and had been a psychiatric consultant to several area nursing homes.

Dr. Farrell was a life member of the American Psychiatric Association, a member of the Federal Physicians Association, the American College of Psychiatrists and a founding fellow of the American College of Psychoanalysts.

He is survived by his wife, Lillian, of Silver Spring; three daughters, Elizabeth Farrell of Salem, Mo., Catherine Farrell of Newton, Mass., and Margaret Farrell of Albuquerque, N. M.; two sisters, Helen Dillon of St. Petersburg, Fla., and Mary Bertrand of Los Angeles; a brother, Joseph E. Farrell of Chicago, and one grandchild.