I seem to recall having read somewhere that Algren later stated (admitted / boasted) that he, in fact, had had no first-hand knowledge of the drug milieu; that he had researched it thoroughly, but only from secondary sources.
Arnold Stang gives a notable performance in the film.
Regards,
What you say may be true. I was referring to the characters Algren created. According to my Dad, right off the streets of the north and west side streets of Chicago to a tee.
Arnold Stang - voice of TOP CAT one of mu favorite cartoons growing up