Final answer:
The claim that deinstitutionalization led to a 75% decrease in the population of state mental health institutions from 1955 to 1980 is true. The policy aimed at moving mentally ill individuals to more humane, community-based treatments, but often resulted in homelessness and increased incarceration due to insufficient community support.
Step-by-step explanation:
The statement you have asked about - whether deinstitutionalization resulted in a 75% decrease in the number of people in state mental health institutions from 1955 to 1980 - is True. Deinstitutionalization was a policy move in the United States aimed at moving individuals with mental illness out of state-run institutions. This movement began in the mid-20th century and was fueled by the development of psychotropic medications, a critical view of institutional care, and a push for community-based services and civil rights.
In California under Governor Ronald Reagan's administration, state-run facilities for mentally ill persons were notably closed and replaced by private board-and-care homes. The deinstitutionalization policy was intended to protect the rights of the mentally ill and sought to offer them more humane treatment outside large, often poorly-maintained institutions. However, many private facilities were ill-equipped, poorly managed, and staffed, which contributed to a significant increase in homelessness and incarceration among the mentally ill population.
Furthermore, federal legislation aimed at addressing the needs of the mentally ill was introduced in the late 1970s, but the shift in policy during the Reagan presidency resulted in substantial cuts to social programs, exacerbating the situation. By the end of the 1970s, a considerable number of mentally ill individuals had been discharged from state institutions, and the capacity of community-based treatments failed to meet the demand. This led to widespread homelessness and other social issues for the mentally ill.