I see homeless who are speaking to themselves like they are hearing voices e.g. schizophrenia and other mental illness indicators more often than not. Maybe being homeless causes symptoms of mental Illness, or having untreated mental illness will force you to not hold a job and be employable like neurotypical workers in SF.
Just because your experience is seeing rampant drug use in the homeless population doesn’t mean it’s the main reason they are on the street. Drug addiction is not mutually exclusive from having mental illness and from having a degree in neuroscience, I learned that being neuroatypical with an imbalanced brain chemistry, e.g. dopamine regulation disorders and other neurotransmitter issues can easily result in the symptoms of risky behavior and substance abuse and addiction, which further damages your brain and neurodegeneration, thus having more mental illness.
Being sober from substance abuse is a huge factor to achieving gainful employment and rejoining society. Having untreated mental illness is increasing the difficulty mode of your life because you are not in control of your full brain if it’s imbalanced and addiction is an emergent neurochemical response to reinforcing pathways in your brain from a hyper pleasurable activity that lights up your imbalanced brain. Sorry I’m rambling but mental illness and homelessness is never really talked about they are destined to be left out of society if they can’t utilize their full cognitive abilities due to untreated mental illness and psychiatric intervention.