A report of 1881 said that of the ten nurses employed at the asylum, five had not yet completed one year's service while of ten male attendants six were in the same position. The Lunacy Commissioners who compiled the report lamented the frequent changes of staff and said these were detrimental to patient welfare.

The 1881 Census, while not revealing the names of individual patients, does show us that the inmates came from a wide cross section of society; the former occupations of asylum residents ranged from a dentist to dressmakers and farm labourers. The East Riding Lunatic Asylum (renamed the East Riding Mental Hospital in November 1920) benefited from general progress in understanding the causes of mental illness. Research into both the biological and psychological aspects of mental illness led to new theories and treatments. Prominent among researchers into the psychological causes was Sigmund Freud (1856-1939) who argued that the source of mental illness lay in unconscious conflicts originating in early childhood experiences. The search for organic causes of mental health problems led to new remedies involving sedatives (like morphine) and the development of deep sleep treatment. More controversial was the use (from 1938) of Electro-convulsive therapy as a treatment for severe depression and in some cases of schizophrenia and mania.
Electro-convulsive therapy (used at both the Broadgate Hospital and at the De la Pole Hospital in Willerby) involved placing electrodes on the temples, on one or both sides of the patient's head, and delivering a small electric current.

In 1946 the National Health Act was passed and Broadgate Mental Hospital (as it became known) ceased to be independent and was now a component part of the National Health Service. During the 1950s the tradition of caring for mentally ill people in large institutions came under intense criticism while in the 1960s the development of new drugs meant that it was now possible to treat patients in the community. During the 1970s large-scale mental institutions were steadily discredited and there was a move away from the isolation of the mentally ill in old Victorian asylums towards their integration in the community.
Locally the numbers of patients at Broadgate Hospital declined from about 450 in 1975 to about 250 in 1986. The East Yorkshire Health Authority faced a situation where it had two large institutions for the care of the mentally ill (Broadgate and De la Pole) both of which were operating at below-capacity and which were becoming more and more expensive to run. With the development of alternative residential care and community-based mental health teams (for example ManorRoad Beverley)
the Broadgate Hospital site became redundant.