Hydrotherapy. Pilgrim State Hospital, 1936 by Alfred Eisenstaedt / Psychiatrists used water therapy to treat mental patients. Hyper patients got warm baths, while lethargic patients received cool sprays. Some doctors, however, used extreme measures, prescribing therapies that seemed more like punishment. Some patients were mummified in towels soaked in ice-cold water. Others were strapped down & submerged in a bath for hours or even days & were only allowed out to use the toilet.
Pilgrim State Hospital - "originally designed to house 12,500 patients on 1900 acres of land" - constructed from 1930-1941 in Brentwood, New York, USA. " . . . holds the record of being the largest psychiatric hospital in the world" when population peaked at 16,000.