Rings of madness: service areas of 19th century asylums in North America.

The mid-19th century saw the emergence of a major medical innovation, namely, the rise of the state lunatic asylum. Beginning in the northeast, the phenomenon spread rapidly westwards. By 1875 no fewer than 71 mental hospitals were opened in 32 existing states. Although premised upon belief in the efficacy of 'moral and humane' treatment, the asylums soon became custodial rather than therapeutic institutions. Average size continually increased; some accommodated well over 2000 patients. The provision of more asylums, and broadened definitions of insanity, generated increasing patient numbers which, in turn, caused public consternation and fear of increasing 'madness' in the population. Geographic analysis of admissions in 18 U.S. states and two Canadian provinces reveals the universality of distance decay around the asylums, and demonstrates that hospital service-area cones were predominantly local in effect. Thus the 'state' asylum was in reality a local institution. The deinstitutionalization movement of recent decades is apparently bringing to a closure a 100-year cycle of incarceration-decarceration of the mentally ill. Nevertheless, whether patients are geographically concentrated or dispersed, the influence of distance decay remains a relevant consideration.