I always remember that scene when thinking about Arkham, because at this point you have to wonder what success means for an Arkham psychologist. After all, it's no longer enough to simply address a villain's underlying issues, you also have to create in them a sanity so ironclad that it won't crumble under the pressure of decades and decades of remembered atrocities. Really, what does a 'cured' Mr. Zsasz look like? How do you 'get over' the sort of things he's done?
Both the epitome and exception to this rule seem to be the Joker. On the one hand, it seems that no one could reconcile the memories he has with leading a normal life; even in the posted story a bit of amnesia is required to grease the skids. But at the same time I can somehow visualize the Joker waking up one day and nonchalantly tossing his weapons into the bin, pawning his purple duds for something in a nice tweed, and taking a job as an assistant bookkeeper. Perhaps for reasons similar to Myxy at the end of 'Whatever Happened to the Man of Tomorrow', or perhaps because he's the only person in the universe who is immune to his own madness, but I feel he could pull it off. He *won't*, of course, but the thing about the Joker is that nothing, not even sanity, is beyond him.