Friends Hospital, originally known as the Friends Asylum for the Relief of Persons Deprived of the Use of Their Reason, was the first private, nonprofit, exclusively mental hospital in the United States and is the oldest continuing such institution. The social and medical concerns which Quakers held regarding psychiatric problems guided Friends Hospital in its physical site plan, the methodology of treatment, and even the manner of its original fundraising. These approaches, then novel, became the model which was studied throughout the nineteenth and early twentieth centuries by others wishing to found similar facilities. The ingenuity of its design, based upon William Tuke's York Retreat in England, but with better ventilation and light as suggested by Philadelphia Friend Thomas Scattergood, was a model for other American psychiatric facilities.
Even more important than the physical layout was the new treatment which Friends introduced - the "moral treatment" of mental illness, a methodology which combined the Quaker religious views of the individual with medical sciences' developing therapies. By the 1850s, the Quaker approach to mental health had become the example for America. Reflecting the Quaker belief in the equality of people, Friends was among the first hospitals to employ women doctors and professional nurses.
The Friends Asylum is historically significant under Criterion A, and its period of significance ranges from 1817 to 1911.