Final answer:
The number of resident patients in state and county mental hospitals has indeed declined since the 1950s due to deinstitutionalization efforts and policy changes, such as those in California under Governor Ronald Reagan.
Step-by-step explanation:
The statement that the number of resident patients in state and county mental hospitals has declined significantly since the 1950s is true. One reason for this decline is the deinstitutionalization movement, which shifted mental health care from state-run institutions to community-based settings. This initiative gained momentum in the late 1960s, particularly under the administration of California Governor Ronald Reagan, and led to the closure of many state-run mental health facilities. The closures were partly predicated on the belief that private board-and-care homes would provide more humane and cost-effective care. However, this transition often resulted in numerous patients becoming homeless or incarcerated due to inadequate support in the community and reductions in funding for social programs during the 1980s.