Over the years many sociologists have contributed theories and research which has enlightened psychiatry in this area (e.g. Avison and Robins); The relationship between social factors and mental illness was demonstrated by the early work of Hollingshead and Readlich in Chicago in the 1930s, who found a high concentration of individuals diagnosed with schizophrenia in deprived areas of the city has been replicated numerous times throughout the world, although controversy still exists as to the extent of drift of vulnerable individuals to these areas or of a higher incidence of the disorder in the socially disadvantaged; the Midtown Manhattan Study conducted in the 1950s by Cornell University hinted at widespread psychopathology among the general population of New York City (Srole, Sanger, Michael, Opler, and Rennie, 1962); the Three Hospitals Study (Wing JK and Brown GW, Social Treatments of Chronic Schizophrenia: a comparative survey of three mental hospitals, 1961, Journal of Mental Science, 107, 847-861) was a very influential work that has been replicated, that demonstrated forcefully that the poverty of the environment in poor mental hospitals lead to greater handicaps in the patients.