I don't a good answer. I'm only known two homeless people with any great familiarity. Both were pretty much homeless by choice and had some affinity to the lifestyle, and neither had drug or alcohol problems that I knew of.

One was normal through college and got a degree but developed mental problems. In spite of family help from both mental professionals and start up money to get her settled into an apartment, she seemed to always end up back on the street. The other seemed to like the carefree lifestyle and didn't mind sleeping in junk cars or flop houses of some sort and would drift from one city to another often following the weather. His father was a doctor and a decent man and the son pretty much had access to money if he wanted or needed it.

I do have an idea for Detroit. I think it should be opened up to some sort modified homestead act.