To me, yes, maybe he, Rick, that cool iceberg of a person of Casablanca, was, god forbid, at one point a writer of some sort.  That one quip of his, about the part of coming to Casablanca "for the waters," says it all.  "I was misinformed."  (Coincidentally the title of a good NY Times blog.)  He doesn't do it anymore.  He quit.  He runs his business, helps out where he can, keeps himself out of trouble, tries to live as neatly as he can, no clingy broads getting tipsy on him and causing a scene without getting promptly escorted home.

You almost see it in his hunch, the night he takes to the bottle upstairs, the solitary habit, almost see a notepad in front of him, as if he were to attempt to write someone a letter, sorting his thoughts out.  But he must have quit, at some point, grown tired of being the exasperating dumb fuck at the whims of the world.  And maybe this is why he came to, of all places, Casablanca.