John Petrou, 94, a certified public accountant and a founding partner of the Psychiatric Institutes of America, died Jan. 11 at a medical center in Gloucester, Mass. He had congestive heart failure.
A son, David Petrou, confirmed the death.
With a psychiatrist, Dr. Edward S. Fleming, and a lawyer, Louis Kaplan, Mr. Petrou opened the Psychiatric Institute of Washington in 1967. By 1982 the hospital had grown into a national chain of health-care facilities, which promoted the concept of treating certain mental illnesses with new psychotropic drugs and doing research that led to wider use of antidepressant drugs.
In 1982, the chain was sold to the California-based National Medical Enterprises.
John Petrou was a native of Haverhill, Mass., and a 1938 graduate of Bentley University in Waltham, Mass. He served aboard a Navy destroyer off the coast of North Africa during World War II.
After the war, he settled in the Washington area and began working for the Internal Revenue Service. He became a certified public accountant and opened his own accounting business in Silver Spring, which he sold in the late 1960s.
Mr. Petrou was a tennis player and an amateur photographer.
His first wife, Bebe Koch Petrou, whom he married in 1944, died in 1984. Mr. Petrou established the John and Bebe Petrou Foundation to support artistic, educational and child-disease research endeavors in the Washington area.
About 10 years ago, Mr. Petrou moved to Rockport, Mass., from Bethesda.
Survivors include his wife of 20 years, Patricia Burns Petrou of Rockport; two children from his first marriage, David Petrou of Washington and Rebecca Lloyd of Potomac; two stepsons, Trevor Burns of Atlanta and Evan Burns of Boulder, Colo.; a brother; two sisters; two grandchildren; and three great-grandchildren.