Well, I do know many of them have mental problems of one sort or another.
With some, it is obvious...

I have a position closer to freedomlover's. I choose not to assume too much about the homeless I encounter....

This morning a homeless woman was in one of the doorways where I work when I got there at about 5:30 this morning...

It was pouring down rain...I just nodded at her and went inside.
She stayed until the rain slowed down, then left...

I was actually homeless for a period of time in my younger days. Lived in my car for awhile. Getting harrassed by the police, etc. I NEVER panhandled...

I was working, but it took awhile to get enough money for an apartment.
That was a fucking long time ago now...