Re Reagan, that's become a myth that transcends fact among Libs and Progs. What actually happened is that in the late 1950s Congress set up a system by which mental hospital patients would be released and receive their meds (which Congress believed to be effective) through community clinics. It was a nation-wide thing, not a California thing. And the releasing of the mental hospital patients began in California during the administration of Edmund "Pat" Brown, who, like his son, was a Dem. The process had been underway for years when Reagan became governor.
What Reagan did that POed unions was to close some mental hospitals that had low patient populations, transferring their patients into other mental hospitals (that also had low patient populations). This reduced facilities and staff costs. To this day there are still mental hospitals operated by the State of California - never closed or "emptied" by Reagan. Many/most current homeless people with mental problems were either young children in their parents' homes or not yet born when Reagan was Governor (1967-1975).