I've had this idea for some months now. I've had the sketches for almost the same amount of time. Its one of the many I doodled up at work back when I had the time for such things.
Funny how those pieces all stacked up to a pile so large that I'd rather have shuffled the little gems to the back of a dark area somewhere than dive in and drown in them. There are quite a few more.

Right then, first things's first - Old joke, new punchline. The joke didn't come from me, but I gave it a little revamp anyhow.

Is this joke making fun of people with mental disorders? Well I certainly hope not! But in the event that you're offended note 2 things;
People are too easily offended and for that I don't care,
and
Sure I could have done a different joke, But then I wouldn't have been able to draw the silly little faces!

Total time, 6 hours.
Enjoy!